Turn Your GBA Into A Game Console
Kon writes "Here's a site that has photos and describes some very nice mods for the GameBoy Advance
(original model), which make it function more like a video game console, yet still
remaining portable. These mods include a Neo Geo joystick attachment, power management
mod, and an RGB LCD monitor attachment. If you're not too squeamish you can try
them as well, using the instructions which are provided."
Don't forget about the PocketNES emulator for the GBA that allows you to play over 8000 NES games on the GBA in full speed. One 256Mb flash cart can hold over 1000 NES games.