Along the lines of Draw Something, I present Map Something, a collaborative, live-updating mapping site. Not a finished project, but pretty cool so far. You can navigate around (i.e. pan/zoom), add points, and delete all points. The really cool thing is that when you do any of that, it updates automatically in everyone else’s browser. Want to show someone where to meet? Navigate there and show them!
Future updates would include tackling line/polygon geometries, selective deleting, and chat.