Former President Bill Clinton stopped by Letterman last night to share thoughts on a whole range of topics, from his foundation to the Occupy Wall Street movement. Bill Clinton will be celebrating 10 years of the William J. Clinton Foundation and the $10 billion it's raised for HIV/AIDS treatment and feeding the hungry on Saturday at the Hollywood Bowl. He's pulling out all the stops, inviting big-named stars and supporters, including Lady Gaga. Last night the ex-pres said she won't be wearing a meat dress, however, since he is a vegan after all. Might we see a plant-based costume creation from Gaga then? Find out which other musicians will be honoring Mr. Clinton and hear his thoughts on much more below.