A 3D printed piggybank for storing Bitcoins
The Pimponator uses an AVR to control a 16 column by 5 row LED matrix. The micro controller has 64KiB of flash memory available for a 6000 frame animation.
A remote control for my TV made using an old NES controller.
A 3D printed mechanical braiding device, created in Blender and printed by Shapeways.com
The CentripetalBox is a 3D printed box with a special lock which only opens if the box is spun quickly.