Unigamer points out Andy Gadget’s Instructable for building an ultra-portable melody/beat box – super cute!

This tiny box will give you hours of fun composing your own tunes. You can vary the tune tempo and switch between a pentatonic and blues scale as well as producing a variety of percussion sounds.
Load up a different program and it will compose its own percussion rhythms(Tic Tac Beat Box) or play with half a dozen different musical scales (Tic Tac Scales). Another cool feature is no power switch – It will hibernate when it’s not being used.

The project runs off of a PicAxe-08M – grab the code + schematic here.