This extended length behind the scenes footage from the film "Avatar", is all about the motion capture performances of the actors in Avatar, and how it works. Using side by side images of scenes from the film next to the actors in their motion capture gear, this doc shows pretty convincing evidence that you are actually watching the performances of the actors and that it is not just computer generated animation. I think this got released at this time because of voting for the Oscar® nominations ending this Saturday.
Not only is it an impressive documentary, but it also changed my opinion of whether or not I was just watching another CGI cartoon. I now realize I definitely wasn't. Watch this film and decide for yourself.