The new Arduino Esplora has been designed to emulate traditional input devices like a mouse or keyboard, and Arduino has developed to not only be a games controller.

New Arduino Esplora Provides A Ready-For-Gaming, Customizable, Open Source Video Game Controller Darrell Etherington 5:59 AM PST · December 10, 2012 ...

With the new Arduino Leonardo board able to emulate USB keyboards and mice right out of the box, it seems the perfect time for Arduino designers to come up with a proper video game controller.

[Tobie Nortje] sure remembers them and has built an Arduino controller to play virtual versions of the games. He started off by finding a website that is digitizing the old games.

Electronics maker Adafruit Industries has developed its own Arduino-compatible boards, including one called the Flora--and a few craft projects to go with them.