Have you ever tried to make a music box?
Well this is my attempt at creating a circuit that plays the musical notes of a song every time someone pushes a switch. For simplicity, both song and player code are compiled together and uploaded to the PIC flash.

The song consists of notes and their duration and thus is stored in a very compact form and the player code occupies around 370 bytes. It's possible to store very long songs using this format which reminds me of MIDI.

Go to the Music Box project page for more information.