An NES gamepad library for Arduino.
One use of this is to allow your Arduino access to the status of 8 buttons (up, down, left, right, A, B, START, SELECT) using only 3 digital pins (for STROBE/LATCH, CLOCK, DATA).
3 pins is a tall order on my Arduino Uno, but for the new Due it’s a drop in the bucket. It supposedly works with the Freedom Stick, too. Wireless Arduino NES Remote here I come.