This Film is Not Yet Rated (2006) http://www.imdb.com/title/tt0493459/
Kirby Dick's investigation of the Motion Picture Association of America (MPAA) film ratings board. The board members are never made public, the guidelines under which they make their ratings determinations are unknown as well.
Dick hires some private detectives to help him find out who are the members of the board. He is able to get interviews with a few ex-board members, which is a feat considering they are sworn to secrecy for life. He also tracks down the membership of the ratings appeals board, which is a different group of people than the ratings board.
Interspersed throughout the footage of tracking these folks down are short history lessons about the board's origin, interviews with filmmakers and actors affected by the board's decisions, comparisons of the inconsistency of the board's ratings across a range of movies, and a bits of watching him try to get this film rated by the MPAA and his appeals process.
Interesting information and entertaining for film fans who are curious about how that system works. It's use of irony and tongue-in-cheek just makes the business seem that much more absurd. Especially when comparing what constitutes 'okay for children to view' as far as violence vs. s-e-x.
I'd recommend any aspiring film makers to watch this as well.
6 years after the making of the documentary doesn't seem to have dated the information any, it's probably just as pertinent today.