The Arduboy, as described by Adafruit, is something of a cross between an Arduino and a GameBoy; with a small screen, directional pad, and fire buttons, in a package the size of a credit card. They also note that it’s “An excellent way to get kids excited about programming as well as a fun way to remember the past and celebrate the retro-future!”
While it looks awesome, and the newer Arduboy FX even more so (as it can store and load 200+ games), they both seem to be sold out as of this writing. The good news is that since the Arduboy is based on an Atmega32u4, with a bit of wiring, it’s entirely possible to build your own DIY Arduboy with parts that you may already have on-hand!
The other potential pitfall, if you want to really get into a game, is that the display is rather small. Now there is a solution for that as well, in the form of the VGA1306 V2.0 Arduboy to VGA output board. As you’ve certainly guessed, the board takes inputs from an Arduboy, or Arduboy-programmed Pro Micro board, and converts these signals into a VGA output for display on a computer monitor or other device. It also has switches that vary the output color, and invert the screen if you so desire. A demo and wiring details are shown below:
Of course, if you use a Pro Micro device, you’ll need some sort of input setup as well. The breadboard Arduboy seen in the clip below may provide some inspiration for how all this could work on a normal smaller screen.