TV B Gone
The TV-B-Gone was conceived by hack-hero Mitch Altman. It is designed emit the 'OFF' code for the majority of TVs in Europe and the US. Basically it is a TV remote control which only has the power button. It is designed to turn off inappropriate TVs, such as unwatched ones in public spaces. It is a commercial product, but Mitch has also worked with Adafruit industries to have an open-source design.