The fact that Thor didn't have an assigned birthday surprised you. You were talking about how you were turning twenty-one this year, how that was a big thing in American birthdays. It would allow you to drink legally, though you never really liked the taste of alcohol.

"We don't really have birth days in Asgard," Thor added nonchalantly. "We live so long that they would be repetitious. After all, what can you give a god?"

You narrowed your eyes at his tone. "You sound like you're reciting text from the Book of Odin."

Thor laughed at the joke, though the smile didn't reach his eyes. "It was my father's rule, never mine. I wouldn't have minded a birth day."

After that, you knew you had to throw him a birthday party. But not just any birthday party. A party worthy of the gods, worthy of Tony Stark's approval, worthy of the thunder god. You recruited everyone for parts of it. Tony got decorations, Natasha and Clint brought the alcohol, Bruce baked the poptart-inspired cake, and Steve kept Thor busy the day of the party.

It was going to be the biggest surprise ever.

You, Natasha, Clint, and Tony wait in the dark as Steve and Thor enter the tower. They'd been gone for a few hours to let Tony have time to decorate.

"Surprise!" you all shout as the lights flicker on, showing Thor the entire penthouse level decked out in streamers, balloons, and confetti canons. One of them goes off just as Thor's face breaks into a grin, confetti falling around everyone.

"Happy birthday!" you exclaim, running to hug your best friend.

"You did all this?" he exclaims, looking around the room and at his friends with puppy-dog eyes.

You nod, giving him a big smile. "Everyone should have a birthday!"

Thor looks down at you, then wraps you in a tight embrace that lifts you off your feet. He swings you around, laughing loudly. "Best birthday ever!"