Released back in 1972 the Magnavox Odyssey is, quite obviously, the first video games console ever. Of course this visionary piece of design by Ralph Baer couldn't really do much when it came to games, but remains a pretty impressive and highly collectible piece of technology. And it sports something not wholly dissimilar to modern-day cartridges; and plays the very first Pong-style game ever (yes, before Pong). You can find out more about the Odyssey over at Wikipedia, the Odyssey Museum or Pong Story, but also try the idiosyncratic OdyEmu emulator.
If you are interested in owning a Magnavox Odyssey and are ready to spend quite a bit, I can't help but suggest you have a look at this Ralph Baer signed Odyssey auction. It's a gloriously boxed specimen in great condition, that has been signed by Ralph Bear and comes complete with the tons of bits the original box included (cartridges, cards, tokens, controllers, overlays, the console and more). Seller ships only in the United States.