Relaxen Und Watchen Das Blinkenlights 2Relaxen Und Watchen Das Blinkenlights 2

To mark its 20th anniversary, legendary German hacker group Chaos Computer Club has built what it calls the world's largest interactive computer display, putting 144 lights in the windows of the top eight stories of a building in Berlin. By turning the lights on and off, the building can display simple text messages, images, and animations.

The club calls it a gift to Berliners, who can submit ideas for images and messages via the Web, and can even call a phone number and play the classic arcade game Pong, controlling the building's display with a cell-phone keypad.