You ever have one of those times when you are sitting in the living room trying to hear music coming from the kitchen or vice versa but you can’t hear it. Then you go to turn up the music in the kitchen and it becomes too loud for those in the kitchen but it sounds good in the living room.
What you need to build is an FM transmitter to transmit that music throughout your house. Sound difficult? It might be the first time to build it, but with these instructions and a few parts, you will be well on your way.
(source – http://electronics-diy.com/tx200.php)