Using two servos, an Arduino and a cheap $3 laser you can provide your cat with endless fun.
Video of the CatBot in all of it's Laser Zeppelin glory below:
Step 1: The Problem
And she's back pawing at it.
The CatBot is the solution.
Step 2: Parts
Hillman Hobby Parts (found @ Lowes in the screws/nuts/bolts area)
$3 Laser cat toy.
Step 3: Disassemble the Laser
Step 4: Cut the Laser
Step 5: Build the Servo Tilt/Pan
Step 6: Wire up the Arduino
Attach the laser to 5v, but 470 ohm resistor inline before the laser.