I think Star Wars Uncut may be one of the most ambitious fan projects ever undertaken. The idea was very simple and involved dividing the whole of Episode 4: A New Hope up into 15 second fragments for fans to claim and to film their own contribution for that scene. The end result would then be the whole movie produced by many different fans, all of which can say they've contributed to the Star Wars universe. It's a pretty different idea and it's produced a style of filming very similar to the "sweeded" concept from the movie "Be Kind Rewind".
Star Wars was a natural choice to explore the dynamics of community creation on the web - the response from fans has been overwhelming worldwide and the resulting movie is incredibly fun to watch.
At last their work is complete and the whole video is now available to watch on their site. So you can head over there, sit back, and enjoy!