mixed marriage - household electronics
You're probably familiar with those little short-range FM transmitters that let you listen to an MP3 player over a car radio. They're usually powered by a battery. Years back I managed to find one that is powered through a USB plug, which makes it ideal to use for MP3 files on a laptop, or for using a computer to pick up streaming Internet audio and get it into the radios you already have around the house. (I can't understand why these are such hard products to find.)
Our TV has a USB socket on the back. On the higher-end models you can plug in a thumb drive and the TV can play MP3s or display JPGs. On our TV it doesn't do anything. But it does have power when the TV is on. (And, bonus, doesn't have power when the TV is off.)
So put the USB transmitter there, connect to the TV's audio-out, grab a headset radio (or a non-iPod MP3 player, which is likely to have an FM tuner) and now you've got wireless headphones for the TV. (Might even work as far away as the bathroom or the kitchen.)
I'll bet none of the parties involved saw that one coming....