Last week this blog featured an interview of Michio Kaku on the Colbert Report, and it turns out that Colbert has actually interviewed several physicists and astronomers.
After his book, From Eternity to Here: the Quest for the Ultimate Theory of Time, came out in 2010 Sean Carroll visited Stephen and attempted to discuss theoretical cosmology - specifically theories of time and why the past is different from the future. As usual, Colbert's antics made for a humorous if not terribly informative interview. You can watch the video here.
Books by Carroll in the Library Catalog