Recently installed the Electric Sheep screensaver on my mac.
The concept, created by Scott Draves, is quite interesting...
The "Sheep" are so called Fractal Flames, generated by a genetic algorithm. They take some time to render and by installing the Electric Sheep screensaver your computer will help render new sheep while it is asleep... it will indeed dream of electric sheep.
The cool thing is that the sheep will evolve based on popularity ratings (you can press the up or down arrow key to rate), they will mate and mix and you can create your own and add them to the gene pool.
On the sheepserver you can watch the lineage and the genome of the sheep (Currently flock 244).