This might be one of coolest mods ever! Someone has managed to stuff an entire playable Nintendo Entertainment System into an NES cartridge. Now technically, it’s not a real NES in there but a cheap knockoff that plays NES games via an emulator but the effect is just the same. You’re playing games on a 2.8 inch LCD screen right on the cartridge itself. Cool. Here’s an action video:
Oh yeah, it plays Gameboy games too! Tetris!!! There’s even a video out port so you can play these games on your big screen. Sweet!