WASHINGTON (October 6, 2012)--Bill O'Reilly and Jon Stewart are tangle Saturday in a sold-out mock presidential debate that's as much about laughs as about politics.

The Fox News anchor squares off with the star of Comedy Central's "The Daily Show" Saturday in Washington.

It's a chance to blow off a little steam amid a heated presidential race.

The celebrity odd-couple has appeared on each other's programs since 2001, exhibiting actual respect for the other's opposing views.

This is their first head-to-head debate.

George Washington University will host "The Rumble in the Air-Conditioned Auditorium."

Half of the proceeds will go to charity.

Unlike the debates between President Barack Obama and Republican presidential nominee Mitt Romney, this one won't air on television, but will be live-streamed online, for $4.95.