I just finished building a music box / light show / jewelry box for my friend Sophie. An Arduino compatible microcontroller is used to generate the music box sound and to control the lights. The Arduino code emulates the sound of an old mechanical box which used a rotating drum with tabs that plucked tune metal tines to produce the note. The code is capable of three note polyphony. This is very easy to build for anyone who can read a schematic. Pictures of the build and links to the Arduino sketch can be had at the link below.