On August 16th I was an observer to a Improv Everywhere (http://improveverywhere.com/) mission. At precisely 6:30p, participants (who had been asked to wear one of a red, blue, yellow, or green shirt) started listening to an mp3 provided by the organizers which they had been asked not to listen to prior to the event. For the next 38 minutes the group of 1000+ people (my estimate) performed a number of zany tasks including group hugs, follow the leader, naps time, & thumb wars. The event ended with an “EPIC balloon BATTLE” between blue/red on one side and red/yellow on the other. I was most impressed with the fact that at the end of the event everyone stopped to pick up all the balloon remnants littering the ground. Way to go San Francisco!