Jimmy Kimmel didn’t want to be left out of all the late night talk, so he decided to dress as Jay Leno (prosthetic chin and all) and do the entire show as Leno.  It was pretty funny as all the jokes were very Leno-ish, and Kimmel’s band decided to play along playing the Kevin role and all the little guitar riffs.  Just add Chevy Chase showing up as Conan, and you got a pretty good bit.