Myself and a couple friends who were on team 4976 last year, built this countdown display for build season. It's a live countdown of the weeks, days, hours, minutes and seconds left until bag and tag.
It runs off the same microcontroller as the Arduino Uno, along with a real time clock and 4, 16-channel constant current LED drivers. Here's a quick video explaining how it works:
https://www.youtube.com/watch?v=SZrxrQ-pmks
If anyone's interested in building something similar, I can provide schematics, PCB layouts, CAD models, and the code for running this one.
Checkout some pictures of the final product here:
http://imgur.com/a/WPZmH
