WiiSpray.

"while not quite ready to fully integrate graffiti into the Wiimote, Nintendo's platform has inspired students and designers to explore the possibilities. WiiSpray is a prototype from Martin Lihs, who prepared it as part of his final at Bauhaus University. Hopefully it will come to fruition, as the idea is fun and rather sound."

I couldn't have said it better myself...really.

via 12oz