David Watts has made a DIY Boombox which is made with mostly off the shelf pieces that have been hacked together. Some of the features the boombox has is line in, bluetooth input, radio, spectrum analizer and a partially working pong game. An Arduino is built into the box to do some of the control. The box is powered from a 6 AA cell battery pack, a step down converter is used to create a nice 5 volt output.