Check out the full tutorial on the Adafruit Learning System
The enclosure is a three piece design that snap-fit together. The bonebox-top.stl part houses the slide switch and audio input jack. The bonebox-case.stl part houses the amplifier and lithium polymer battery. The bonebox-bottom.stl part houses the bone conductor transducer exposing the vibrating metal piece but is secured in place with built in clips on the bottom part.
The parts are optimized to slice with MakerWare and printed using PLA with no raft or support material.