Graffiti Research Lab and friends hacked together a high powered projector with some computer components and a camera to track the writings of a 60mW Green Laser on the side of a building in Rotterdam and project it as blue graffiti. The resulting art looks surprisingly good, and the perpetrators were kind enough to document the event, along with providing instructions for doing up your own version. It's hard to describe, so we recommend peeping the video after the break, or the better quality vids and pics over at the read link.
