The Muralizer is a device that hangs on a string, automatically drawing the design of your choice on your wall. And hopefully, it'll be a kit you can get yourself in the near future.
You plug it into your computer and load it up with the vector art of your choosing, hang it up on a string on the surface you want to draw on, and let it do its things. If it's sold as a kit, it'll be a couple hundred bucks and will require a bit of soldering, but it seems like a great way to add some cheap art to the blank wall of your choice. [Muralizer via Make]