President Obama's traffic-stopping visit yesterday included a final visit to the Ed Sullivan Theater, where David Letterman is winding down his late night talk show career. Obama confessed he mainly came by to say good-by to "Biff...Paul" but said he was told he had to see Letterman if he was there.

They also discussed their retirement plans. Apparently during the commercial break, the president told Letterman that he was going to take a month off after leaving the White House. Letterman exclaimed, "Are you kidding me? After eight years of this, you're only taking a month off?" Then Letterman joked that he would be teaching law at Columbia.

The President also answered a Dumb Guy Question:

Earlier in the show, there was also a very special guest in the audience—Harry Caray.

Letterman's final show is May 20th.