Relaxen Und Watchen Das Blinkenlights

Using the face of a building to flash messages into the night, legendary German hacker group Chaos Computer Club has built what it calls the world's largest interactive computer display.

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.