Note: This is A Mario Story. (aka A Christmas Story. But it has almost nothing to do with that movie.)
If you don't celebrate Christmas, at least you can celebrate the Mario characters being stupid about it.

"A little to the left," Luigi called from the sidewalk.
Mario leaned a little further and almost fell off the ladder. "Now?" He asked, looking ready to fall.
"Hmm..." Luigi took an annoyingly long time to decide. "Nah, I think it should be more over."
With a groan that could probably be heard two blocks down, Mario reached a little harder. "How bout now?"
"Hmm... You know, I think it'd look better on the other side."
Mario, who was spent to his last ounce, finally gave up and crashed to the ground. A pile of snow from the roof followed and covered him.
Luigi, who was looking over his two mile long Christmas preparation list, pretended not to notice.
It was an extra special fine day in the Mushroom Kingdom, and snow had finally blanketed Toad Town. The air was practically ripe with peppermint and ominous music wherever one went. So, as you can gather, it was Christmastime.
Mario loved the time of year, mostly because of the food and the fact that it snowed naturally all the time. That meant he could frolic and dance in it all day and no one blamed him for it.
"Mario! Get up your lazy carcass! Now it's time for the power!" Luigi instructed.
Mario, who was panting as if near death, came up for fresh air. "Tell me why... you take holiday decorations so seriously?"
"Because, we're famous! A billion people practically drive by our house every winter and we have to look snazzy."
"We can look snazzy at the Christmas party," Mario whined. "Can't you get someone else to do your manual labor?"
"Like who?" Luigi raised an eyebrow.
"I don't know... Yoshi!"
Just then Yoshi came walking down the street with Birdo. He froze. "The answer is no," he called before he could get recruited. "We're on our way to the castle on special orders from the princess, so don't even think about it!"
Mario groaned. "Gee, thanks."
"Well sheesh Mario, you're practically the only strong human guy around who can actually do all that stuff! Which reminds me, the princess wanted you to go help at the castle too."
Mario buried his face directly into the snow. Luigi, meanwhile, had finally found the extension cord and plug, and stuck it in. A fantastic explosion worthy of New Year's went off and Luigi jumped a mile before landing in the snow smoking.
Yoshi and Birdo stood there and stared at the display that had lit up their house: aside from the usual wreaths and bows and garlands and icicle lights, colorful light up mushrooms adorned the roof and front porch. The yard was littered with candy canes that went absolutely nuts with the red and green.
Rosalina glanced up from her reading. "What is that light outside?" She asked the Luma lounging nearby. He got up and peeked out the bedroom curtain.
"Hmm... I'm gonna guess an atomic bomb," he said, surveying the planet below, then went back to his seat.
At that moment a toad passed by on the sidewalk. "Hey Mario, nice house! Can you do mine?"
Mario lifted his head from the snow. Then he put it back down. And he didn't come up for a real long time.

At the castle, everything was the farthest thing from orderly.
"Get those garlands over here! Toadette, I need you to clean up that juice spill! You two, bring that ladder! Oh, Blue Toad, get your hands out of that pudding pie!" Toadsworth snapped. He put a hand to his head and sighed. "And WHERE are those Christmas petunias?!"
"They're poinsettias," Yellow Toad corrected beside him.
"Whatever!"
The toads were busy preparing the hall for a big Christmas party that night, and it was all going just peachy. Which was ironic, since Princess Peach had been unable to help due to baking all day.
Toadsworth, as you can see, was in charge, and he was just loving it.

Toadsworth: If I may say so, I am not exactly 'loving it'...

NintendoJedi: It's a sarcasm.

In the kitchen, Peach and Daisy were cooking their crowns off for the zoo they knew they were gonna have to feed. Toad, who was helping do weird stuff like knead bread and scrub egg whites off walls, grumbled the whole time.
"I am gonna barf the next time I see another jelly donut," he was saying, feeling positively sick after eating a ton of batter.
Daisy shrugged. "Okay, just make sure you clean it up afterwards."
Meanwhile, The bros had finally arrived with Yoshi and Birdo at the front gate. When Toadsworth heard, he rushed out to meet them.
"What took you rascals so long? I almost grew white hair in all this time!"
"Um, Toadsworth, you already have white hair," Yellow Toad pointed out beside him.
"Yes, thank you for pointing that out, Yellow Toad," he said flatly.
"Well, I had to find my Christmassy outfit, and my Christmassy cologne, and my Christmassy hairstyle, and my Christmassy attitude," Mario explained. "And that's what the holdup was. But we're ready to party now."
Mario and Luigi had changed to their fireflower outfits to fit the mood.
"Oh, you're ready to party now, huh?" Toadsworth asked. "Well I've got a better job for you: put on this!" He dumped a big Santa suit in Mario's arms.
"What?" He asked, clearly stupefied.
Luigi laughed and scratched his head. "Oh yeah, I guess I forgot to tell you..."
"Forgot to tell me what?" Mario demanded.
Yellow Toad didn't hesitate to clue him in. "You're gonna be Santa for the Christmas party!"
"WHAT!?"
"It's orders of the princess!" He quickly defended himself.
"You see, we needed someone to dress up and talk to the kids," Toadsworth explained. "Basically... the only one good for that job is you."
"Why me? I'm, like, eons younger than Santa! And I don't even have a beard!"
"It's part of the costume, bub," Blue Toad said, passing by with a box of day-old crumpets. Mario almost snatched one when Luigi pulled him back.
"Listen, Master Mario, it's not hard," Toadsworth said. "I'm sure you know the standard Santa procedure."
"But Santa is fat! Why can't you get someone like Wario to do it?" Mario complained.
"Um, because Wario is like, bad with kids, dude," Luigi said. "He would sit on them. Literally sit on them."
"And when's the last time you weighed yourself anyway?" Yellow Toad added.
"Hey!" Mario snapped. "I'll have you know that Christmastime is the worst of the year for me! And I'm unusually slim this year!"
Toadsworth waved a hand. "Yeah, great. Just put that on right away! The party's not too far off now."
Mario shot Luigi a gaze of daggers. "I have a feeling this is your fault," he said.

Shortly thereafter the rest of the guests started rolling in. Luigi had been tasked with standing by the door giving everyone name tags, and according to him the guest list was about 200 people long. Rosalina came dressed as Ms. Claus practically, with Polari accompanying her. Wario and Waluigi showed up wearing ridiculous elf costumes, because not even the princess could refuse inviting them at Christmastime. The instant they walked in the door they acted as if they owned the place.
"Hey look, they laid out crumpets for us!" Waluigi said loudly, ready to raid the food display.
Wario snorted. "Ha! Crumpets! That's the dumbest word I've ever heard!"
Just then he spotted Mario, who was sitting on this fancy Christmas display in his Santa getup, trying to hide his dark mustache that didn't really blend. Wario's jaw hit the ground.
"O M Goodness," he said dramatically. "Is that SANTA?"
Waluigi froze. Then he tapped his chin. "I dunno."
Wario was by his side faster than physically possible for a fatso of his caliber. "Santa, I want a billion bucks' worth of gold coins, a thousand adoring servants, and some dumplings smothered in lard and criso," he said beggingly. "I've been amazingly not bad this year! I helped the princess take care of a baby once, and I only talked smack about Mario's mustache about a dozen times!"
Santa's eyes popped. "You did WHAT?!"
Wario ignored him. "Hey, speaking of, you sound an awful lot like an annoying little gnat I know," he said. "Are you a fake?"
"Fake?" Waluigi asked. "Santa's a fake?! Nobody is allowed to cheat but me!"
"Okay, um, thank you, that's enough," Luigi said, coming to the rescue just in time. "Santa's not available for visitors now!"
When they had gone elsewhere to stir up rebellions, Luigi turned to him. "Maybe you should try to act more like Santa," he suggested.
"I am acting like Santa!" Mario replied, trying to hide his face in the beard. "I even have to say 'HO HO HO' instead of 'HA HA HA' when something's funny!"
"Yeah, well, maybe you should get rid of the mustache," Blue Toad suggested, passing by with a platter of cookies. "It kinda ruins the look."
He might as well have asked Mario to cut off his hand. "YOU SAY ONE MORE WORD ABOUT MY MUSTACHE AND YOULL BE ON THE NAUGHTY LIST FOR ALL THE REST OF YOUR MISERABLE LIFE," He said so loudly everyone in the room looked up. Someone dropped a glass and it shattered.
Luigi took the chance to make a scene. "Oh, look what you did!" He said to the random toad who did it. "I need a broom over here..."
Luckily everyone forgot about it after that.
By eight o'clock the rest of the guests had arrived. On top of a billion toads, koopas and shy guys, Bowser and Bowser Jr. also showed up, on special invitation. When they walked in the door there were some uprisings.
"Hey everybody, let's get this party actually started!" Bowser said as he strutted in. Toads and koopas alike responded by shrieking like baby girls and running into walls.
Luigi looked over the guest list. "Name?"
Bowser rolled his eyes. "It's Bowser, genius."
"Opinion of the worst Christmas song?"
"Ooh, Oh Christmas Tree. That's like the dumbest song ever, man! It says your leaves are so unchanging, but have you ever looked at a Christmas tree in my used Christmas tree yard? Those things are like red as apples! How did they get away with such a blatant lie?"
Mario was still sitting around mostly just looking pretty at that point when Bowser spotted him.
"Hey, look who it is!" He said stupidly, coming over with Junior. "Santa, long time no see! I haven't seen you since that time I tried to steal your reindeer."
"How charming," Mario said, pretty sure that Bowser was just being dumb.
"Oh, Santa! I have a really long list for you this year, so you'd better get to work!" Bowser Jr. said, waving the paper in his face. "No excuses!"
Mario rolled his eyes and looked it over. "A new clown car... a million coins... a monument... a baby brother?!"
Mario groaned. "Look, I don't mean to crush your dreams, but that's not happening."
"Why not?"
"I can't make babies."
"Why not?"
"Uhh... cause I'm too old."
Bowser Jr. frowned. "Daddy, I don't like this guy!"
"Yeah, well me either," Bowser said. "I don't even care how bad I've been. I ate a billion donuts this year and kicked a billion minions and once when I was in Mario's house I accidentally dropped his razor in the toilet."
"WHAT?!"
"But I put it back and everything was fine, in my defense," Bowser went on. "Anyway, I believe we have a meatloaf bar to raid. Later, old dude."
They left Mario sitting there looking ready to barf. Blue Toad joined him.
"Getting too old for this job?" He asked.

Last but not least came King Boo and some minions. When he appeared by the door Luigi promptly fainted.
"Hey, if it isn't my old pal Baby Luigi! What's going on, plumber boy?"
Just then Bowser looked up from where he was boasting by the dessert bar. "Hey King B, glad you could make it!"
They spent about thirty seconds doing some long drawn-out handshake thing while everyone stood around feeling weird. Then Santa came by to drag Luigi away.
"Oh yeah, just hide the body in the bathroom or something," one of the boos called.
Mario hid him under the dessert table instead.
Finally when the party had started and the loud Christmas music cranked up the princess came out. Yoshi had been forced to dress up as a reindeer in antlers and sleighbells and made to stand by Mario.
Princess Peach was in her fireflower dress as well. After greeting everybody, she announced that it was time for all the kids and babies to meet Santa.
So, for the next like twenty million years, Mario and Yoshi hung around the Christmas display talking to baby toads.
"What's your name?" Mario asked the one on his lap.
"Paul," he said.
"And how old are you?" He asked, going through the same old Santa procedures.
"Four," he replied, holding up four tiny fingers.
Peach and Daisy were standing back watching and nearly gushing at the adorable display. Blue Toad was unsupervised in charge of the music, and now he was playing 'Walk Like an Egyptian'. Birdo came over later and cranked on jazzy instrumentals that better fit the mood.
For some reason, interspersed in the Santa line were some of the other party guests, such as Bowser and Bowser Jr. again. When they came up, Yoshi had to crush Mario's foot to keep him from groaning aloud.
"What do you people want for Christmas?" He asked unenthusiastically.
"Well, Junior here already told you what he wants," Bowser said.
"If I don't see at least a million coins you're going to be a dead man," Bowser Jr. added.
"Gee, I'll keep it in mind," Mario said.
"Anyway, I want some stuff myself," Bowser went on. "Not a whole lot. I was just hoping for a princess of my own, you know, maybe a couple of planets to rule, and if it's not too much trouble, the power to utterly crush my most hated little enemy Mario into a plumber pulp. You know."
Mario rolled his eyes. "Well maybe if you're a really good boy next year..."
Meanwhile Luigi had crawled out from under the dessert table and nearly had a cow when he saw Santa Mario talking to Bowser. Before he could say anything the line had moved on, however.
Finally all the kids had been seen and Peach came over to them. "Nice job, Santa!" She patted Yoshi the Reindeer. "Oh, and you too, Blitzen."
"Who decided he was Blitzen?" Yellow Toad asked, overhearing. "I was calling him Cupid!"
They ignored him. Peach turned to Mario and giggled, "But I never got to tell you what I want for Christmas!"
"Oh, what's that?" He asked innocently.
She grinned mischievously and said, "Hmm... just this."
When she planted a kiss on his nose Yellow Toad turned around and barfed his brains out, along with several other colorful sugary cookies. (No, not really.)
Luigi sighed in exasperation. "That's not what Santa does," he said loudly after about five seconds.
Finally Mario said, "And that's for being such a good girl this year!"
"Thank you Santa," Peach said as she guiltlessly slipped away.
Luigi had had enough. Just when he was about to go rip his beard right off his face and expose him as a fake, a scream went off from the kitchen.
"SHRIEEEEEEEK!!"
Mario was there in no time flat. (Well, actually it took him 7.43 seconds, but that's not important.) Daisy, Toad and Toadette were beside themselves with worry.
"What happened?" Mario asked.
"The huge Christmas cake we made," Daisy said. "It's gone!"
"Whoa, whoa, whoa," Mario said. "What do you mean GONE? How big was this cake?"
Toad gestured with his tiny arms. "Huge!"
"It doesn't look that big to me," Mario said thoughtfully. "Maybe you just misplaced it."
Daisy shook her head. "No, this thing was ginormous," she said. "And it was stolen from this very spot."
Mario put his hands to his head. "Oh no," he said. "But if it was stolen then that means... NO CAKE!!"
Toad and Toadette looked at each other. Mario looked at them imploringly. "How did this happen?!"
"What I want to know is, how did you get out of that Santa outfit so quickly," Daisy said, looking him over.
Mario shrugged. Then Peach came into the kitchen and sighed. "I really don't know what happened," she said. "I guess one of the guests must be responsible... or else we have a thief."
"A cake thief!" Mario said. "Worst kind!"
"Mario, do you ever think about anything other than food?" Toad asked.
"What else is there?" He asked, deadpan. Everyone blinked. Then Mario laughed. "Just kidding... of course I do!" He stepped forward and took Peach's hand. Toadette sighed happily. Yellow Toad stuck his head around the corner and almost barfed.
"I'm going to find that missing cake," Mario declared. "I'll stay up all night if I have to!"
Just then there was another scream from the main hall. Mario rolled his eyes. "Now what!?"
When they came into the party room they were surprised to find the koopalings harassing the guests in one big group, performing what looked like some sort of hostage. Bowser was there among them, doing what looked like bad parenting.

Bowser: For the last time, I am not their father!

NintendoJedi: Last you said, you were their father.

"Hey! What's going on here?" Mario demanded.
"Mario! They're trying to crash the party!" Luigi cried. He had been tied to a chair with what looked like a piece of licorice.
Mario rolled his eyes. "It's just a bunch of kids, Luigi, grow up."
Everyone stared as he came forward and kicked Bowser's foot.
"Hey! What was that for?" He asked.
"Trying to ruin our party by sending your goons to crash it!"
"I didn't plan this!" Bowser said. "I didn't even invite them!"
"Neither did I," Peach spoke up.
"Yeah," Ludwig growled. "We NEVER get invited to the parties, in case you never noticed."
"Well we're sick of it!" Larry announced. "We always have the most fun anyway. Enjoy your cakeless party!"
Mario's jaw hit the ground. "How dare you."
Morton grinned. "Oh, we dared, plumber boy."
"Would you people quit using that term?!" Luigi snapped.
Peach stepped forward while Mario began to twitch uncontrollably. "Listen you all, I'm sorry if you were offended," she said. "I never really thought to invite you. It isn't exactly in my best interest, you know," she added glancing at Bowser suspiciously. "But in the spirit of Christmas, and since you're already here, it would please me if you all stayed to join us."
The koopalings looked at each other and then back at Peach. Then they looked at each other and then back at Peach again. Then, Ludwig nodded. "Agreed. Wendy, get the cake."
Iggy pulled open the front door and Wendy pulled it in, a giant monstrosity of frosting on a big cart. When Mario saw it he let loose a river of drool on the ground.
"The cake!" Daisy said, rushing over to make sure it was unharmed. "How did you blockheads get it outside?"
"That's um... classified," Roy said.
At this point it didn't really matter. Everyone was freed and the cake was soon cut, with guests bouncing around to Sleigh Ride while Luigi supplemented his own lyrics. King Boo and Bowser were strolling around as gaily as they could while still looking bad, Bowser tossing tinsel everywhere while badly singing.
"Deck the halls with Bowser holly,
Gwa ha ha ha ha, haha ha ha..."
King Boo was confused. "This place is quite terribly happy for my tastes..."
Bowser shrugged. "Well, that's how it is on Christmas. You get used to it."
Meanwhile Yoshi and everyone else were having a blast on the dance floor and eating the cake and whatnot, which turned out to be better than Mario had hoped. After his third piece he took a rest to watch from nearby.
At his side Luigi appeared out of nowhere. "HUG ME BROTHA!"
Mario pushed him back with surprise. "Not here man, there's people around," he said.
Luigi looked hurt until Mario sighed and said, "A quick one."
Then they did their special version of what can only be described as a half-second hug.
"Oh Mario," Luigi suddenly spoke up. "Guess what?"
"What?" Mario asked carefully.
"You standing under the mistletoe."
Mario's eyes popped. Then he ran while half the party chased him down the hallway and around the castle and finally back out into the dance floor and...
Let's just say Christmas parties are always sorta like this at Peach's castle. The koopalings laughed and the toads were having a good time and the boos were faceplanting in the pudding. The baddies were making messes and Luigi actually had a dance with Daisy and...
No one went to bed until about four in the morning. What actually happened on Christmas Day, with the gift giving and all that junk, is actually quite uneventful compared to the times when everyone gets together and tries to actually get along. But perhaps that's a story for another time.

And that's what could possibly happen if the whole gang got together for a Christmas party. If it seemed kinda short, I was trying to keep it down, but I don't know how well it really turned out. Mostly I just wanted it out before Christmas ;)
King Boo's first line is actually mostly recalling the first thing he says to Luigi in Luigi's Mansion 2. Another kind of fun thing, when Mario says he only ever thinks about food, that was actually a small conversation from one of the old Mario shows (I guess back when Mario really did just think about food all day).
Anyway, in the spirit of Christmas. Here is a really amazing rendition of Sleigh Ride by a YouTuber in the guise of Luigi. Merry Christmas!

[There should be a GIF or video here. Update the app now to see it.]