Flockmod: Interactive drawing for the modern age
Oce Eeco stashed this in Web Treasures
Plenty of tools to draw anything and features allowing to correctly moderate a room.
Registration isn't required, you can go as an anonymous user.
And, of course, a lot of nice people to meet in this (at the moment) very little community.
Direct link to default room: http://drawdevil.com/fallback
Sweet. I wish I could draw.
I'm very bad at drawing, I still go there because I meet and chat with people from everywhere. Even if you're a total noob, collaborative drawing is very funny.