Thanks to the good people at the Internet Archive, classic console video games like Donkey Kong, Mario Bros., Asteroids, Dig Dug, and Pac Man are now fully playable online. The games, released as the Internet Archive Console Living Room, are also available for free downloads. They don't have sound yet, but the archive promises to get that up and running soon. And even though the collection isn't complete at this point, the archive promises to expand it "in the coming months." Because the archive has versions of each game available in an browser-based emulator, you can jump right in to the game of your choice without downloading any specialized software. 

ET: It hasn't improved with age. 

Right now, the archive contains a selection of games from the Atari 2600, Atari 7800 ProSystem, ColecoVision, Magnavox Odyssey and Astrocade. The selection is particularly abundant for the Atari consoles, but as the archive notes, "there were many not-excellent cartridges produced for the Atari 2600," meaning that some of these games aren't really worth the time to get to know. For instance: the archive contains ET: The Extra Terrestrial, a game so bad that someone made a documentary about its failure. On the other hand, there's always Frogger, which is still excellent. 

Some of the games even come with the original manual, which if nothing else, gives a good glimpse at the conceptual imagination behind the very sparse graphics game designers had to work with at the time.

The Internet Archive's project is aimed at preserving a widely-unavailable software phenomenon, as the consoles and cartridges needed to play these games have largely disappeared. The rise of the home console, as they note, more or less destroyed the popularity of arcades, especially once console graphics began to approach the look of arcade offerings. And as each console evolved, the previous generations also gathered dust or were tossed out.

Players will note that the controls vary widely by console: the Internet Archive does a pretty good job explaining how the games have adapted from, say, a joystick control to a standard keyboard. And even though these games are old, the Internet Archive recommends players use the most up-to-date browser possible.