Writing a gameboy emulator is probably the most rewarding hobbyist project I've ever embarked on. Not only is the process educational and enlightening, but it's hard to describe the satisfaction of playing Tetris on an emulator that *you wrote*.
An emulator from scratch is not a small undertaking, but the Gameboy is well documented, and just simple enough that's it's possible for one person to write an emulator on their own. I recommend it to everyone! In this talk I'll show some of the highlights of the journey, and what to expect if you embark on it yourself.