This is a documentary that relates the history of the American Hippie community. It's full of archival films, but also has quite a few new interviews of the original cast members. As a bonus, there is a portion of a second documentary. This one relates the technology and history of Light Shows as relating to musical events.
I am just a little too young to have personally tripped through the landscape of the 1960s. So, this type of documentary is a next-best-thing.