On September 11th, 2001 the famous “Haus des Lehrers” building at Berlin Alexanderplatz was enhanced to become world’s biggest interactive computer display: Blinkenlights. The upper eight floors of the building were transformed in to a huge display by arranging 144 lamps behind the building’s front windows. A computer controlled each of the lamps independently to produce a monochrome matrix of 18 times 8 pixels. During the night, a constantly growing number of animations could be seen. But there was an interactive component as well: you were able to play the old arcade classic Pong on the building using your mobile phone and you could place your own love letters on the screen as well.

via blinkenlights.net