COLUMBIA, S.C. — Sen. Barack Obama did a cameo on "The Late Show with David Letterman" last night, giving a Top 10 list and joking with Dave about how the host mussed up former Sen. John Edwards' hair recently.

Among Obama's list of his "campaign promises":

"Appoint Mitt Romney Secretary of Lookin' Good"

"If you bring a gator to the White House, I'll wrassle it"

"I'll rename the tenth month of the year 'Barack-tober'"

"Pronounce the word nuclear, nuclear"

Here's some video:

Sen. Hillary Clinton has been on Letterman many times, but she dazzled the comedian this summer by reprising some of his jokes about her pantsuits.

Here's that clip:

Here's the video of Letterman and Edwards from earlier this week.

Edwards, who had a huge crowd last night in a sort of homecoming in Seneca, is attracting some voters who are tired of the Obama-Clinton squabbling. (Here's my story in today's paper from the campaign trail.)

Some shots from yesterday:

I'm hitting the road on an admittedly ambitious quest to try and see all three candidates — and their spouses — today in the Palmetto State. Polls open tomorrow at 7 a.m.

— Christina Bellantoni, national political reporter, The Washington Times