A few from Alpha Phi Omega:
Bill Clinton (we all know who he is)
Robert Gates (current Secretary of Defense)
Carson Kressley (from Queer Eye for the Straight Guy)
Bob Love (former NBA player - one of only a few players to have his number retired by the Bulls. It makes me smile every time I go to a game and see his number in the rafters!)
James Lovell (astronaut)
Tom Daschle (former Senate majority & minority leader)
Tom Keane (former governor of NJ, chairman of the 9/11 Commission)
Naraht and a couple others maintain a really good list
here.