Do you read Kevin Charnas? If not, why not? He has a great blog. It veers from the sublime to the just plain silly. This? Would be the latter. Do not drink beverages while watching this video. You have been warned.
I saw this on another blog and had to swipe it. It's fantastic. The group is called Improv Everywhere and they do guerilla improv. It's great stuff. Get thee to YouTube and have a look.
And this ad from the Superbowl kinda creeped me out.