As you can see, the light not only turns on and off, but the lampshade is knocked off when hit by your "iGun." BANG! is the creation of Taiwan-based Bitplay and one of the creators told me it was born out of a laziness to get out of bed in the winter to turn out the light. Essentially this is the Clapper 2.0.
Personally, I don't want any kind of gun in my home, but confess that it was kind of fun to play with this light setup and it was the most unique idea I saw at the fair. For now, BANG! is only available in Asia, but bitplay was at NYIGF looking for a U.S. distributor and I'd be surprised if they didn't find one.
See more: BANG! at bitplay