Check out the trailer for "An Inconvenient Truth", a film about the life and environmental message of Al Gore (who "used to be the next President of the United States of America").

I've read and heard from people who have heard Gore give recent talks featured in the film, and the consensus is something like "expected a dry speech, but found it captivating and motivating." Seems hearing this message can get you fired up.

Judging from the trailer, it's definitely something I'll try to see.