Nobody would survive high school -- or Hollywood -- without a sense of humor. That's why everybody loves a class clown. At Hollywood High, Jim Carrey is the guy doing impressions of the teacher behind her back, while Sarah Silverman sneaks a whoopee cushion underneath her chair. Steve Carell is the kid with a sarcastic answer for every question. Paul Rudd may look innocent, but he has the teachers fooled -- he's the one streaking across the football field when their backs are turned. And Tina Fey is the comic mastermind behind those brilliant senior pranks. How did they get the principal's furniture onto the roof, anyhow?