Just prior to last week's No Pants Subway Ride (AKA: No Pants 2k8), a few improv-appreciating activists went on a mooning spree of the blue kind. The nerve!

But don't take our word for it, check out all of the shocking naked-butt action, above. And in front of the Irish Bank, no less! (Brilliantly brought to you by Viddyou's nahduhlee's.)

To check out some photos of the naked BART riders, do visit No Pants 2k8's Flickr page. Laughing Squid also has some choice shots.