The flash (GQ-4X from mcumall)
Yay, now I can program my own computer chips! This guy takes the game code, sends it down the USB cable and writes to the chip with the game code. I'm not entirely sure how it all works, something to do with timing, light and electrical impulses. And probably magic. Regardless, what comes out is a crispy new NES game, whoo-hoo! ;-)
this cart rebuild is pretty easy to do, in fact... more people should play around with this stuff IMO, and you could even make a little business selling custom or hard-to-find carts to your friends, or at conventions. all the ROM dumps are already online.