Classic video games from the 1970s and 1980s have been put online by the Internet Archive and can be played within a web browser for nothing.
The collection has launched with games from five early home consoles, including the Atari 2600 and Colecovision.
The games do not have sound, but will soon, the Internet Archive said.
"In coming months, the playable software collection will expand greatly," archivist Jason Scott wrote.
"Making these vintage games available to the world, instantly, allows for commentary, education, enjoyment and memory for the history they are a part of."
The other machines included are the Atari 7800, the Magnavox Odyssey (known as the Philips Videopac G7000 in Europe) and the Astrocade.
Well-recognised titles such as Pacman, Space Invaders and Frogger are all in the archive - with more consoles and games expected soon.
Unlike today's titles, which are stored on disks or even simply downloaded directly to a console, many older machines would use bespoke cartridges to store games.
As the consoles fell into disrepair and became ever more scarce, playing these games has become difficult.
For many years, communities of gamers have created ROMs - read-only memory - images of games. These files can be played on a normal PC by using an emulator.
However, in many cases, gaming in this way can be illegal - particularly when the games involved are made by the likes of Nintendo and Sega, which clamp down on such activity, deeming it a form of counterfeiting.
But older games such as the ones found on the Internet Archive fall into something of a legal grey area.
Publishers and developers often turn a blind eye as, with the games no longer available to buy, the ROMs mean the titles are still able to be played by many.
Yet with smartphone gaming on the rise, publishers are now in a position where these old titles can be revived, cashing in on the timeless quality of the games, as well as fans' nostalgic urges.