Darkeru from the Ben Heck forums came up with the idea for this beauty, and after months of "careful planning," finally finished his creation. It's exactly what you think it is; a mod that plays NES games on a NES game cartridge. What an ingeniously simple idea (though if we really think about it, our brains might implode).
The games are built into the portable -- ninety-nine of them, in fact -- which sounds pretty convenient. Other than that, we have nothing to say except that we're still gawking at this thing. Oh, and do want.