Digital Graffiti Wall for Converse
via vimeo.com
I just stumbled on Alex Beim's work - what a great find! this interactive graffiti project allows you to 'pick up' colours from the palette with the spray can and then paint the screen images.
Reminds me of the lovely MIT I/O Brush (2005), which allows you to paint with still & motion capture videos. If you're interested in the tech, there's a great discussion in the comments below on Beim's use of infrared in the can which is picked up by a camera behind the multi-touch screen. Very cool work.