I was asked to join the Microsoft Coding4Fun team this year at Maker Faire. The project I came up with was multiplexing several stock store bought signs and display full motion video from a webcam on them... Unfortunately it's almost impossible to do full motion with stock parts, so it evolved into a "LED photobooth."
The signs are BetaBrite Prisms, the software is written in c#.
The software is driven by many c# examples derived from the web:
It was two very long days.