it's gotta be Robin Hood: Men in Tights. I'm not a huge fan of Mel Brooks, but Robin Hood is a classic comedy movie. It's got really good acting, the story is good, and it's a perfect spoof of Robin Hood Prince of Thieves with Kevin Costner. My favorite line is when Achoo (Chapelle) says to Blinkin, the servant "Hey, Blinkin", and he replies "Did you say Abe Lincoln?"