In what was perhaps the last official joke of yesterday's April Fools Day, John McCain dropped by the David Letterman Show for a brief stint on stage.

Among the highlights: McCain, according to Letterman, "looks like the guy who points out the spots they missed at the car wash." Letterman, according to McCain, looks "like a guy caught smuggling reptiles in his pants."

Meanwhile, McCain's visit to his Virginia alma mater, Episcopal High School, was a bit more subdued.

The boldest inquiry came from junior Katelyn Halldorson, who asked what exactly the senator was doing at her school. "I think judging by the amount of press representatives here and also by the integration of your previous political endorsements in your earlier personal narrative, we can see that this isn't completely absent--er, political motivation isn't completely absent," she said. "Yet we were told that this isn't a political event. So what exactly is your purpose in being here--not that I don't appreciate the opportunity, but I'd just like some clarification."

"I knew I should have cut this thing off. This meeting is over," McCain joked, before launching into a long description of his biography tour and it's emphasis on "the values and principles that guided me, and I think a lot of this country in the past." He said he also hoped to provide voters with "a vision of how I think we need to address the challenges of the future."

McCain concluded the visit by saying, "I hope that attendance here was not compulsory...I apologize if you were unwillingly in attendance here."

Here's a clip: