Bill O’Reilly is a right-wing interview talk show whom I do not particularly care for. His program (The O’Reilly Factor) airs on Fox News Channel and he also has a radio show (The Radio Factor).
Stephen Colbert is a comedian/satirist and hosts The Colbert Report, an ongoing parody of The O’Reilly Factor airing on Comedy Central. I have never seen an episode (in its entireity). He generally is not as funny as the hype would have one believe. To be fair by the time I saw my first Colbert bit (the notorious “truthiness thing) I was already sick of reading about the guy; there was no way in heck he was ever going to live up the hype. Stephen Colbert’s present program is a spin-off of the Daily Show.

As part of a large comedy bit and publicity stunt Bill O’Reilly went on the Colbert Report and earlier in the evening Stephen Colbert was “interviewed” by Bill O’Reilly.

Both segments are actually funny.