
This dice by Rickard Gunee is interesting because it uses one of the smallest microcontrollers, a 6-pin PIC10F200. With 4 GPIO it’s just one pin more than the voltage regulator. Using multiplexing it controls 4 strings of LEDs and even one input button. The whole project is open source and also available as kit.

My daughter is very interested in the LED dice. Where can I pick up this kit?
http://www.guneetech.com/shop/product_info.php?cPath=21_23_29&products_id=42