Celebrity Marathoners
 

Found this list on wikipedia. A few of them surprised me:

Dana Carvey, Ocean to Bay Marathon 1972 (3:04:21)
Very impressive. He ran that time when he was 17.

Clarence Thomas, U.S. Supreme Court Justice, Marine Corps Marathon (3:11:xx) 1979

John Edwards, Former United States Senator, Marine Corps Marathon 1983 (3:30:18)

One that was surprising for the wrong reasons:

Mario López, Saved by the Bell, Boston Marathon 2002 (5:41:41)
A 13:02/mile pace. My guess is he thought he was in better shape than he was, didn't train, and the distance kicked his ass. He had to have had a sponsor's exemption to get into Boston. But hey, at least he finished.

http://en.wikipedia.org/wiki/List_of_marathoners

I refuse to believe that Oprah completed a marathon. I say that she payed someone to run it for her.