Two Sure Electronics DE-DPP004 4" seven-segment character displays in series. Driven by an attiny24. There are three buttons and a status LED (which is currently not really used, but it's hand for debugging).
Datasheet: http://www.sure-electronics.net/mcu,display/DE-DP004.pdf
Video: http://www.youtube.com/watch?v=6szSFfxwtfc
attiny and PIC (XC8) source here.