I am not big into documentary films, however I found a film that I should mention on here. Its for the people who are into comic books, Comic Book Confidential. This is a must see for comic book fans, it talks about how comics began along with the beginning of the underground comix era. It even has interviews with comic book creators such as Will Eisner(The Spirit), Robert Crumb(Fritz the Cat, Mr.Natural), Art Spiegelman(Maus), Frank Miller(The Dark Knight Returns, Sin City) along with a few other people like Jack Kirby and Stan Lee.
If there is anyone who hasn't seen this documentary movie from the 80's, go see it. Its that good.