I'v blogged about 3d printed satellites HERE before, but PongSats are new project I found. Basically they are launching ping-pong ball sized nano satellites to the edge of space with helium balloons.
Video of the full flight:
3D printing files fro PongSat can be found on Thingiverse:
PongSat Users Guide:
Main company site with lot of cool content, ideas and balloon launch photos: