So - instead of a 'Cat Ball', we will just call it a 'Cat Toy'. It has a PIC12F1840 at the heart, a piezo speaker to play sounds / music, two LEDs (green and red) for color, and a vibrating motor I scrounged from an old cell phone.
As always, here's the schematic:
Crowded! There's a lot on this little board.
The ugly underbelly. I was more concerned with fast than pretty.
And a short movie: