I enjoy an occasional documentary. They don't usually have the budget, stunts, or special effects that most movies do, but it is refreshing to see something very realistic as opposed to so much fake stuff we see at the movies. I know not all documentaries are created equal and some are definitely more honest than others. Over the years I have seen many documentaries and some of my favorite have been:
Bigger, Stronger, Faster
King of Kong
My Kid Could Paint Like That
If you haven't seen these I would recommend you give them a shot. I'm sure I'm missing many others. Feel free to recommend any documentaries you may have enjoyed in the comments section.