The other day I was driving behind a green Prius with a bumpersticker that said "MARS, BITCHES". It made me laugh, though I had no idea what it meant.

A little Googling showed it was from the Dave Chappelle show, which used to be on Comedy Central. I found the sketch in question on the Comedy Central website. It's a series of bits about a black version of President Bush. The Mars reference is in the last one, about 6 minutes in. Note: not audio-safe for work, or for those easily offended. (It's the one in the lower right-hand corner, titled "Black Bush".)