I love stuff like this. Im hearing the raphaelJS name a lot so it's nice to see what can be done with it. I just assumed the library was for drawing charts? But I guess it's more for vectors.
Anyway - what I'm really looking forward to is realtime multiplayer / multiuser versions of all these great demos. Just think of the viral/network effect. I'm sure it's all quite possible now that we have node.js?