Letterman underwent quintuple bypass surgery in January 2000. While he was recovering, a number of celebrities served as guest hosts, including Bill Cosby, .\r \r In 2007 Zach Galifianakis, master of the one-liner, performed at the famed Purple Onion in San Francisco one of the funniest acts in recent comedy. Want to see .\r \r Look Who It Isnt was a DVD that Zach Galifianakis self-released. It features clips from his VH1 show, Late World with Zach Galifianakis, as well as stand up clips.\r \r Zach Galifianakis taking his monologue to a preschool. Its a clip from his prematurely cancelled show on VH1 called Late World With Zach aired during the .
