well, you ca ntry buildnig your circuits, for fun, and use them, all kind of ir, radio, oprical, analogue sending, digital....etc
i have bough a pair of haedphones,wireless, on FM 433MHz with the range of 100m ,they work all the way in my house, good quality, stereo. they work very fine. but the only disadvantage is that the audio frequency goes only op to 18KHz,. but still not many people hear sounds over that frequency, so i dont mind.
i thing that instead of buildnig a circuit of your own, buy a pair like that, even if they are a little bit more expensive.