Heard about this on the radio -- you sign up and when your computer is idle, it participates in the generation of some gorgeous (and mundane) screen animations.
Check out Electric Sheep):
Electric Sheep is a collaborative abstract artwork founded by Scott Draves.
It's run by thousands of people all over the world, and can be installed on any ordinary PC, Mac, Android, or iPad.
When these computers "sleep", the Electric Sheep comes on and the computers communicate with each other by the internet to share the work of creating morphing abstract animations known as "sheep".
Anyone watching one of these computers may vote for their favorite animations using the keyboard. The more popular sheep live longer and reproduce according to a genetic algorithm with mutation and cross-over. Hence the flock evolves to please its global audience.
You can also design your own sheep and submit them to the gene pool.
The result is a collective "android dream", blending man and machine to create an artificial lifeform. Learn more about it.
Here is one of their animations:
