Kal Penn has a pretty unusual resume: He has starred in Harold and Kumar, the most successful series of stoner movies made in the past decade; and has served in the White House as the Obama administration's liaison to youth. Now he's hosting a new show, The Big Brain Theory, on the Discovery Channel.
We've invited him to play a game called "Ahhh! Get It Off Me!" You might be surprised to learn you're not alone in your body — there's a whole colony of bacteria and other critters called a "microbiome" living there. We're going to ask Penn three questions about our little unseen friends.