Australian hacker and Arduino enthusiast Steve Dalton has created a simple and useful interface for the Pandora Radio service which is streamed using a Raspberry Pi. He has used a Freetronics Eleven Arduino Uno-compatible board, and by replacing the bootloader with a human-interface the Eleven can be used with the piano bard application as a simple like/don't like/next track controller. Although the hardware is at the minimal stage, with some buttons and an enclosure it would make a great product.
To replicate this yourself, visit Steve's project page here. And for more, we're on twitter and Google+, so follow us for news and product updates as well.
If you're going to reproduce the project above, check out our Freetronics Eleven - the Arduino-Uno compatible with low-profile USB socket, onboard prototyping space and easy to view LEDs: