Gameduino is a game adapter for Arduino (or anything else with an SPI interface) built as a single shield that stacks up on top of the Arduino and has plugs for a VGA monitor and stereo speakers. The sound and graphics are definitely old-school, but thanks to the latest FPGA technology, the sprite capabilities are a step above those in machines from the past. The adapter is controlled via SPI read/write operations, and looks to the CPU like a 32Kbyte RAM. (Unlike many 8-bit machines, there are no restrictions on when you can access this RAM). There is even a handy reference poster (which you can download below) showing how the whole system works.

Brand:	Tinkering Supplies
Brand Part Number:	4518
Our Part Number:	h4518