Celebrities that have guest starred on the show include Tom Arnold, Thora Birch, T.C. Boyle, Pete Carroll, Chris Colfer, Anderson Cooper, Michael Cunningham, Colin Farrell, Tom Hank, Eric Larson, Bill Lawrence, Jason Lee, George Lucas, Alfred Molina, Nobel Prize Laureate George Olah, Mark Prior, Richard Riordan, Josh Schwartz, Gary Sinise, Steven Spielberg, Patrick Stewart, Diane Watson, John Williams, Robert Zemeckis and more.