Star Wars fans should get a real kick out of this. A gentleman by the name of Michael Heilemann has put together a pretty amazing film that examines the cinematic influences behind George Lucas' Star Wars. The film is part of a research project for an ebook Heilemann is writing called Kitbashed, and while its a work in progress, you can actually view the film so far right now in the player above.
If you're into DVD extras like I am, this is fascinating. You can also head over to the Kitbashed site and check out shorter videos and articles that take individual pieces of the film and look at their influences.