I've occasionally mentioned Improv Everywhere and their missions — they're great, and there's a documentary on them now, called, appropriately enough, We Cause Scenes. Here's the trailer:
You can get the entire film here (12.99 USD; it's also on amazon, iTunes etc., but you're going to pay extra to pay the middle man that way). I've just finished watching it, and wow, it was fascinating. Two quotes really stood out to me, too:
People forget about what it's like to play. And this is playing, and it's playing for adults.
And (referring to IE's first MP3 Experiment):
It was one of those things where your face literally hurts. I could not stop smiling.
That's how Improv Everywhere's videos often make me feel, and how this documentary made me feel. Go buy it and watch it.