I thought to do a search on YouTube for “Mousey the Junkbot” and found this video. It does a good job of demonstrating the bot’s photovoric behavior. On the Colbert Report, or at the Maker Faire, or other situs where Mousey has been demo’d, the light is too defuse, so the sensor action isn’t really demonstrated. The set up in this vid, where there’s a single light source and gradations of darkness around it, is perfect; you can clearly see Mousey’s tendency to want to “eat light.”
More Mousey links on Street Tech.