A while ago I found this YouTube video where a guy sings songs about Star Wars to the tune of popular John Williams songs in four part harmony with himself. It gets stuck in your head, let me tell you, and Brad and I frequently find ourselves singing it. The kids especially love the wookie part, and will often randomly yell out "wookie!" Brad makes a wookie noise by covering his mouth with his hands and warbling, and the kids' impression of him is hilarious to us.
By the way, the camera scared Nick at first. That's what's happening in the first part of the video.