Step 1: buy a business card holder that looks just like a Famicom cartridge. Step 2: crack that card holder open. Step 3: put the guts of a cheap, emulator-capable media player inside.
And voilà! You have a Famicom cart that can play Famicom games. Perfect in case you find yourself stuck at a party with people that would be impressed by this kind of thing.
modder squeezes famicom into famicom cart (sort of) [technabob]