http://www.myoats.com/create.aspx/ "Myoats is a community where people create designs using an online drawing application. These designs can be rated, downloaded, and archived. The Most Liked designs are rewarded by being featured on the home page."
Thinking (Level Design) with Portals. Not too surprising after hearing Valve's Portal 2 comments (they used it extensively during level design and there is still something like that in the game, where they had to use an invisible Portal to make the level fit). Cool idea, though.