I had a TVBGone for a few days but it kept going off and the battery died and then I lost it. As a result, I was sad. This seems like a better solution than the keychain model, however. You simply slide your zipper down to a certain spot on your hoodie, closing a hidden circuit, and LEDs inelegantly embedded in the hoodie will turn off the TVs surrounding your vicinity.
MAKE has the full plans and they even describe a TVBG hat that you can use to give yourself telekinetic powers.