I read an article in the November edition of Wired magazine on how you can build stop-motion animation films using Legos and fairly cheap Web Cams (many of which -- including the Logitech Quickcam -- come with built-in stop motion animation software).
The idea with stop-motion animation is that you move the objects on your set a fraction, take a picture, move them a fraction more, take another picture, and so-on (the goal being to have 15 frames or pictures taken per second to simulate smooth movement).
There is now a whole community built up around doing these types of movies with Legos. http://www.brickfilms.com/ is a great resource to learn more on how it is done (there are several great articles about the techniques, software to use, etc). There are also a number of cool (and some downright weird) movies that people have posted.
I bought a cheap webcam and spent an hour or two over the weekend animating a Duke Blue Devil mascot (complete with soundtrack). I have to admit it was pretty fun. Here is my Oscar winning contender: http://www.scottgu.com/movies/bluewithmusic.zip