AVR Dice is a simple electronic dice based on a ATtiny44 microcontroller. See it in action: https://youtu.be/rQY-iaz-Fag
More documentation will probably be written later. The circuit is quite trivial though; there are just a bunch of leds, some resistors, a buzzer, a button, and a transistor for driving the extra bright leds that are located on the bottom of the enclosure (for the lighting effect that is displayed when rolling ends)