The designers over at iStrategyLabs are all about bringing social media into the physical realm. They have created such "social machines" as a fridge that opens to reveal cold beer after 10 people have checked into it on Foursquare, and a cake that speaks your tweets when you use a certain hashtag.
The Paintbot is their latest creation. Just tweet using the hashtag #ISLPAINT and the paintbot will shoot a paintball at a whiteboard. As many commenters on the iStrategyLabs have suggested, it would be particularly awesome if the paintbot were equipped with a camera and a live feed so that people could watch their tweets get turned into paintballs in real time, but it's still awesome just to know that such a cool machine exists.