Retro gaming consoles aren't just great because they play nostalgia-enhancing, and often genuinely awesome video games. They're also really easy to hack.
Take this project by X over at Instructables - which has managed to fit an entire NES Nintendo gaming console onto a NES cartridge.
This kind of thing would have blown our minds back in 1991, and it's still pretty impressive now.
The system includes two controller ports and hooks up to a TV just like a regular NES. Take a look at the video above for how it works, and be sure to read the full story here.
Now if only someone could hack a NES onto a NES controller. Wait... Oh, right - they have.