The Internet Archive has launched a dedicated section called The Console Living Room, with descriptions and background information on the first games consoles that hit living rooms around the world in the late 70s and early 80s. But that's not the best bit. Not only is there some cool resource material about the consoles, but you can also play a vast majority of the games that were available on them. In your browser. For free.
Some of our favourite games of all time are available among the hundreds on offer, including Space Invaders and Defender for the Atari 2600 (aka Atari VCS). There are also games for the Atari 7800 sequel machine, which include a decent version of Donkey Kong, the ColecoVision, the Magnavox Odyssey2 (aka Philips Videopac G7000), and the Astrocade.
No sound is implemented in the games as yet, but the Internet Archive is currently working on that area and hopes to have that running soon.
Check out the entire archive at archive.org/details/consolelivingroom. And watch out for those tricky invisible invaders around level 90 or so.