I got it as a gift - but I found it online. It's called the "Lightcast Interactive Music Lightshow". It only has 3 plugs on it - Power, Line In, and Line Out. Feed your TTS out through a separate sound card and into the line in on this thing, then through the line out to your TTS speakers. Here's a detailed "ad" I found on yourtube describing and showing off the unit:
http://www.youtube.com/watch?v=OM5ybDe4tiYFor the awesome effect, it is mounted 1 inch below the frosted glass on my desk which I frosted myself with a roll of frost tint from a local home improvement store (Home Depot, Lowes in the US).
In reality though, any "light show" type device that utilizes the simple line-in method could be used... This unit happened to fit and LOOK just right, as it's circular and multi-colored... Makes me think of an upgraded HAL.