If you haven't taken the time to watch French street artist JR's 2011 "TED Prize" talk, do so now. The Inside Out project is one of the most inspiring and comprehensive examples of art-as-social-change that I've seen in a long time. And the best part? It's open to everyone. Go on people, get involved.
Working anonymously, pasting his giant images on buildings, trains, bridges, the often-guerrilla artist JR forces us to see each other.