Woodstock - 3 Days of Peace & Music (The Director's Cut)
An incredible documentary that is the closest you can get to being there. While it is worth it for the music alone (the Who, Jimi Hendrix, Richie Havens... everyone from the sixties except the Beatles and the Stones, basically) there are some nice little asides where we actually see the people who were there. For those of us who are merely the children of the boomer generation, it's nice to see them when they were young and... well, not your parents.
Get a haircut HIPPIE! Just kidding. This was awesome!