Wetpaint isn’t just a wiki tool, it’s also a tool for collaborative art: wetpaintgroupart.com
Thanks to the (highly addictive!) suggest-me-a-random-website-toolbar StumbleUpon I found this cool service.
Start your own art project from scratch here: Wetpaintpleasetouch.com
Or add your stuff to my own creation “Hornstull” (based in its turn on someone else’s work):
