Conan

(11 p.m., TBS) - Actor Bob Costas; actor Mike Zohn; actress Evan Michelson.

Late Show With David Letterman (11:35 p.m., CBS3) - Actor Robert Downey Jr.; comic Lisa Lampanelli.

The Tonight Show With Jay Leno (11:35 p.m., NBC10) - Louis C.K.; Levi LaVallee; Common performs.

Jimmy Kimmel Live (midnight, 6ABC) - Kathy Griffin; Jamie Bell; Young Jeezy performs.