The Goal of this Instructable is to introduce you to the wonderful world of emulating video games
Step 1: Smartphone.
Have a Smartphone, preferably Android, and make sure you have a reasonable amount of space. Each game is 2-7MB, so if you're going to download a hundred Gameboy games, make sure you have a Gigabyte available.
Step 2: Download.
Go to your phone's app store and download a Gameboy Emulator. There are many emulators, but the one that has worked best for me is My Boy! Free.
Step 3: Games.
After the successful download of the emulator, the next step is games. In the emulator world, games are referred to as Roms. To "Find" a game you are looking for, all one must do is google the title of the game with the word Rom after it. go to a website and collect.
***Disclaimer, The legality of this step is gray. Only download Roms of games you physically have.
Step 4: Optional: Play in Style.
You might think when playing, "Wow, this game is taking me back to my childhood, except pressing glass instead of buttons ruins the remembrance". Well fear no longer.
For $6 you can get a Wireless Bluetooth Gamepad that you can play your emulator with
Simply follow the directions to turn it on and sync it and most phones will automatically recognize it as a gamepad and the emulator will let you use it.
Step 5: Contuined
There are many different types of emulators. You could emulate a Gameboy color, or go newer with a DS emulator. To do so and simply repeat the steps with searching for whatever system you are looking to emulate.