Interactive Windows, Plays Pong.
Shops will do anything to try get you inside and purchase their wares, from annoying scrolling LED signs to 42" Plasma tvs...well here's another one to top it all off, from what I can deduce from the google translation, the Centre for Advanced Visualisation and Imagery at the University of Aarhus have developed a window based on electrochromatic glass that essentially changes opacity depending on the position of a viewer. They have also integrated the ability for it to animate and entertain...

Link via Engadget
Link via Comon (google translated)