NES in an NES Cartridge
Let's take Moore's law even further. The computing power needed to play the original Super Mario Bros. on the Nintendo Entertainment System is just a fraction of what's available now, and in much smaller sizes. That's why it was possible for a user named "dany32412" on Instructables.com to put all the inner workings of an NES inside an NES cartidge.
All the parts are there: the connectors for two controllers, the power switch and even a port to plug in other NES cartridges. No word on whether you have to blow in each cartridge before it will work, though.
This hack is made possible by a Chinese clones of the Nintendo Famicom that basically puts all of the power of the NES on one chip. Once you get your hands on that chip, you could pretty much put an NES into any object. Now all someone needs to do is make a game console out of completely ridiculous things. Perhaps a NES inside of deck of Magic cards? An NES Optimus Prime? An NES in a sandwich?
The sky's the limit.