Rick Perry

Texas Gov. Rick Perry, after offering up late-night fodder with his forgetful moment at this week's Republican presidential debate, opted to get in on the joke with an appearance on David Letterman's show Thursday night.

Capping a day of interviews in which he tried to laugh off the embarrassing moment, Perry gave the TV audience his own list of "Top 10 Rick Perry Excuses" for being unable to remember which three federal agencies he would eliminate.

In a separate interview on Fox News Thursday night, Perry explained that the campaign decided to have a "little bit of fun with it." His campaign website invited people to comment on which agency they'd like to forget -- Perry said the site got over 2,000 hits Thursday.

On Letterman, Perry chalked his brain freeze up to everything from Mitt Romney's good looks to a deficiency of energy drinks.