What do computers dream about?

Electric Sheep is a poetic screen saver that uses the distributed computation to visualize the "collective dream of sleeping computers" (ie. cool looking fractal animations).
You can get some sample movies from the website, as well as a documentary with artistic and technical explanation.
Scott Draves's article gives an interesting overview of how the sheeps are born, bred and evolved.

Another interesting kind of mutations: animating walking characters via evolution.

Update: A DVD was made from Electric Sheep animations. You can get it online from Spotworks.