Ecotonoha
Okay, this is straight out of late-90’s dot-com euphoria, but it’s still pretty cool, if mainly useless: Ecotonoha, some sort of weird topic-less message board that arranges posts like branches and leaves on a tree. The more posts, the bigger the tree grows, and the greener it gets. You can even click on a leaf and zoom in on its area, seing branches and leaves hidden behind it, or in its general area. Lots of pure randomness in those messages too, since you’re limited to an arbitrary 37 characters in your message, there’s a lot of Zen in there too. 
