The Spherebot would be a great way to design some unique Christmas Tree Ornaments.
“Our Spherebot is made of two stepper motors and a servomotor; as mentioned, a motor serves to rotate the ball on the axis, while the second motor allows to move the marker around the circumference of the sphere. The servomotor is used to raise and lower the pen. To allow anyone to easily edit the software without the need for programmers or compilers a bit of Arduino would be ideal.”
Via: Dangerous Prototypes