"Classical music attendees across the country are being treated to a videogame in concert halls that lets them conduct an orchestra through a rendition of the William Tell Overture, Tchaikovsky's Fifth Symphony or Berlioz's Symphonie Fantastique. The game is simpler than Guitar Hero;"read the rest here.
and more details here:
Wave the baton too slowly and the orchestra arrayed on the screen plays the "William Tell Overture" at a crawl. Wave it too fast and the music gallops away.