Musician and inventor Aleksei R. Stevens has created a concept product called the SoundBall. The SoundBall is a soccer ball that is filled with motion sensors that detect when the ball is being rolled, dropped, kicked, or spun. The motion data is then transmitted over Bluetooth to a local computer that bleeps out corresponding electronic noises.
My guess is that he's got some kind of Arduino or Parallax board inside the ball and Cycling '74 Max/MSP music software running on his computer. Whatever he's using, it looks like a fun way to kill some time and annoy the neighbors. I can't wait until someone comes up with a cat toy version!