Stereolive

This is way cool. It's a 'live' stereogram that you can manipulate in real time by wiggling your mouse.

In case you don't know, a stereogram is a kind of trippy 3D optical illusion. They became a quite popular fad in the 90's - you might know of them as 'Magic Eye' pictures. They're really cool and interesting to look at, and can also be useful for relaxing the eye muscles after prolonged bouts of staring at a VDU.

There's some viewing instructions here. It can be quite difficult to see them at first. Stick with it though, I think it's worth it.