Imagine how cool it would be for Fred and George to accidentally time travel to the marauders era (after sirius turns out to be innocent)

They would completely hit it off with James and sirius, prank Peter all the time and torment him for his betrayal and be so shocked how their former dada professor can be so mischievous and devious

But most importantly aside from half of the lot being dead (which is really sad) they would have the time of their lives and it would be so interesting to write all the different characters interacting with one another!