The Cloud Harp isn't new, but it is a harp played by clouds. It's a big Quebecois machine which fires infrared beams up at the clouds and translates their bumps into music, apparently sounding like "bad Autechre". Unless my French is failing me, this page says it was actually installed in Battery Park on September 11th 2001, which sounds to me like the premise for some fantastically pretentious modern opera. More here. (Thanks, Joe and Engadget)