The Dexia Tower in Brussel, Belgium has 4,200 windows that each have a remote controlled RGB LED bar that basically turns the entire building into a huge glowing chameleon-like Vegas light show.
Creative Review notes, "Dexia, a bank, opened its Tower, next to the Rogier Metro station at the end of one of the city's main thoroughfares, last year. Ever since, it has played host to a series of amazing light shows, mostly courtesy of Brussels-based LAb[au], specialists in interactive artworks and audiovisual performances. Playing while we were there was Who's Afraid of Red, Green and Blue? (above), one of a series of six different works, each lasting two months. The current show is on the theme of weather."