This a robotic juggler built by the Department of Control Engineering at Prague's Czech Technical University. Researchers have taught this machine to lob and catch five billiard balls all on its own. It'll someday do the same with our skulls.
The juggler model consists of two mechanical vertical arms that are used for juggling as in the case of a human juggler. Each of these two arms is composed of a carriage, moving in the vertical direction and carrying a smaller motor. The actual arm is mounted on the motor and is able to move horizontally. Thus the arms are able to toss over a ball between each other on a parabolical trajectory. A high-speed camera is placed in front of the juggler to detect the movement of individual balls and to close a visual feedback of the actual ball position.
And here it is from a different angle in three-ball mode. It's a less heavy metal view, but you get a better look at its various mechanisms.
[Via Hack A Day]