Watch George W. Bush Tell a Dirty Joke

Well, "ribald" may be a better word for it.

Talking Points Memo points to the “ribald” humor former president George W. Bush displayed during a speech yesterday in Austin. The occasion was a summit marking the 50th anniversary of the Civil Rights Act, held at Lyndon Johnson’s presidential library.

“Former presidents compare their libraries the way other men may compare their, well…” Bush said.

Maybe he hadn’t heard about Colbert taking the Late Show gig, figured he still had time to get his name out there for a chance to succeed Letterman.

The joke comes at just after the 40-second mark in the video above.