Flip the Bushman

Here's your chance, W's in free fall and you can grab that dude by the scruff and fling him around to your heart's delight.

Play Chess with Thinking Machine 4

While you try in vain to defeat the Brain, watch it's mental calculations sketched on the screen...

Dreamlines

From the creator's intro: "Dreamlines is a non-linear, interactive visual experience. The user enters one or more words that define the subject of a dream he would like to dream. The system looks in the Web for images related to those words, and takes them as input to generate an ambiguous painting, in perpetual change, where elements fuse into one another, in a process analogous to memory and free association."
Tip: it keeps on going!