We haven't watched a documentary in a while, but I really enjoyed Dirt the Movie.
When I saw all the people involved, I thought, "well, this is probably old info for me" etc. But then I decided I should see it since it was so many wonderful experts and doers all in one film. I wasn't disappointed. There's probably something for everyone to learn even if fairly knowledgeable. For my average compatriot, there's lots!!