This is completely home made xylophone made with CNC milling machine. But to be it completely awesome Nerdkits have made it automatic by adding also home made solenoids that actuate each sound by hammering bars with bolt head.
They made xylophone universal that could be interfaced to any microcontroller board. It accepts serial data stream that is paralleled with shift register. This way you need 3 MCU pins to drive eight solenoids. And of course shift register is an additional protection of MCU from solenoids. There is a simple example program playing tunes with Atmega168 microcontroller.