This is quite interesting. I wrote previously about interactive architecture... but this is actually interactive virtual vandalism! A 2500- 4000 lumen projector is more expensive than a paint spray can, but the implications are huge. (Watch the video here and pics at Flickr) Can you imagine sending a text message from your mobile and having that text projected with virtual graffiti somewhere? (say, a wall on your girlfriend's house) That would be wicked!