Okay, it's not strictly robotics related, but the code was developed by the Imperial College Robotics Society.... and it is totally awesome.
You're not supposed to be able to turn a computer into an FM radio transmitter with software alone... but this works. Yes, it works much better and over a greater range if you add a little piece of wire as an antenna... but if you get your radio close enough then it works purely using the Raspberry Pi completely unmodified.
It is a great demonstration of why circuit board designers have to watch for interference when working on higher speed circuits.
I'm sure many people who have Pi's have already seen the link, but maybe if you don't have one, knowing that this works... perfectly... might be what you need to go get one. By themselves they are nothing special... but the Pi has developed an Arduino-like following that really makes it something special. Check it out...
tutorial, video and code are here.
Jason