In comedy, it's tough to make it to the top, but it's even harder to stay there. Sure, Will Ferrell, Jack Black, Sacha Baron Cohen, and Steve Carell have muscled their way onto the A-list beside Jim Carrey, Vince Vaughn, Ben Stiller, and Adam Sandler, but a movement is already afoot to displace them, or at least follow in their footsteps. With Knocked Up, Superbad, and Hot Rod, a trio of comedies with no established names above the marquee but plenty of laughs, the summer of 2007 is shaping up as one for the ages and has Hollywood reevaluating its idea of what's funny. Have a look at the hottest new faces in comedy.