Here is another great project by Adafruit. You can build you own portable Gameboy clone and load it up with one of many custom ROM packages. I wish I had the time to build this, but it will go to the bucket list.
Detailed build guide on Adafruit learning system: https://learn.adafruit.com/pigrrl-raspberry-pi-gameboy
|Made by Thingiverse user djecom|