This was done by getting coordinates from the MacBook’s sudden motion sensor and routing it into keyboard strokes (arrow keys), then sending it to an online game of Pacman.  
NEW: You can do this by downloading and running the new Tilt2Joystick application. This is a standalone application that will allow you to play games and [...]

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In order to create this effect, you’ll need to know how to run Max/MSP, and load the following objects:
Fiddle
aka.booklight
Here’s the patch I did, but there are countless variations.

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