Fallout, Fallout 2, and Fallout Tactics are free on GOG.com for the next 48 hours

Online games retailer GOG.com is giving away copies of Fallout 1, Fallout 2, and Fallout Tactics for free as part of its 2013 winter sale.

For the next 48 hours, the three classic RPG's will be free to download, DRM-free, for registered users of the site.

The three games will disappear from the GOG.com catalog at the end of the year, as original series publisher Interplay will lose the rights to publish the original Fallout games on December 21, 2013. Anyone who has already obtained the game will be able to redownload them from the site after this time.

The site's winter sale will continue until 13:59 GMT on December 29, with the company saying that over 600 games from its library will be sold for half-price until then.

Additionally, the site will be running time-limited deals, user votes, and a series of mystery box discounts for registered users.

Earlier this week GOG.com introduced a worldwide 30-day money back guarantee for its titles, promising a full refund for users who cannot get their purchased games to function on their machines.

The Fallout series has recently seen an enterprising hoaxer attempt to persuade the public that a Fallout 4 announcement is imminent, with Bethesda officially distancing itself from the prank, although another suggestion that Fallout 4 is in development and will be set in Boston has resurfaced overnight.

If you're about to embark on the original Fallout for the first time, here's some advice: don't worry about the time limit.