It's already been around a while, I know, but it's worth sharing again.
A group of fans made a remake of the first Star Wars movie. Every fan got a slice of 15 seconds and could do with it whatever they wanted. You got computer animation, kids playing C3PO, a female Darth Vader, Lego shootouts, whatever you can think of. Scenes shot in an office corridor can be followed by the same scene outside an apartment building in twilight, followed by a mid-day shot on a grass lawn. It's ranging from crappy looking to professional work. All in all, it's geek love made manifest.
What I only found out about today (but expected would happen as soon as I heard about A New Hope): they're also going to do The Empire Strikes Back. It's already in production (which I think means that fans have submitted all the material?), so it should be available soon.
Enjoy.