With its "Blinkenlights" project, the group put 144 bright lights in the windows of the top eight stories of a building in downtown Berlin. By turning the lights on and off, the building can display simple text messages, images, and animations.
Tech-savvy Berliners can also submit ideas for images and messages over the Web, then see them displayed on the building. They can even call a phone number and play the classic arcade game Pong on the screen, controlling the action with a cellular phone's keypad.
Chaos Computer Club built the display to mark its 20th anniversary and as a gift to the city of Berlin. For more information, go to www.blinkenlights.de.