Johnny Knoxville: Brian Smith/Corbis Outline; Men in Black 2: Melinda Sue Gordon

Johnny Knoxville

ROLE The two-headed alien Scard/Charlie

WHAT'S HOT He's the funniest nondog aspect of the movie, and what's hotter than some good comic relief? Meanwhile, on MTV's ''Jackass,'' it's hard to take your eyes off this fearless freak as he engages in questionable activities like setting himself on fire.

WHAT'S NOT How many gross-out stunts can we watch before getting bored?

WHAT'S NEXT Taking his TV show to the big screen in ''Jackass'' and developing a half-hour comedy show for Fox