Flash-mobs are random, awesome, fun, and awe-inspiring!  Wikipedia defines a flash mob as a large group of people who assemble suddenly in a public place, perform an unusual action for a brief time, then quickly disperse.  These spontaneous group performances reveal that there are people out there are working to make something fun and awesome, and giving it to others without expecting anything in return.

To find or participate in local flash mob and related events, check out http://www.flashmob.com/ and http://improveverywhere.ning.com/