Streetpong adds a small touchscreen to the buttons usually used to trigger traffic lights to change. When someone presses it, a game of Pong starts up. But to make the idea really cool, if there's a person on the other end of the intersection, then the two people play against each other until it's safe to cross the road.
German students in a design course first developed the basic idea in 2012. They put out a video showing how the concept would work and started a company to make it a reality. Just recently, there was a grand unveiling of the system actually running in the city of Hildesheim, Germany.
Scroll down to watch Streetpong working in the real world and the original concept video. Both are in German but with English subtitles.