GOG.com (good old games) turns one tomorrow and will celebrate by offering a free Interplay game for every Interplay game purchased. In other words: buy one, get one free.

Speaking to Eurogamer, chief mouthpiece Lukasz Kukawski said the promotion runs until 7th September. That means a trip down memory lane for games like Fallout 1 & 2 won't break the bank. Those games, incidentally, are GOG's best sellers.

GOG.com had also planned to give one lucky user the entire Interplay catalogue for free - a saving of around $100 - but there are "too many legal issues" to get this out on time.

GOG.com launched in beta form last September, counting support from only Interplay and Codemasters. Today, there are over 140 games available to download, DRM-free. GOG hopes to continue this "snowball effect" over next couple of months, and entice other publishers with "huge back catalogues".

"Every announcement of new publisher joining GOG made other publishers think, 'We also have some back catalogue games, why not release it on GOG?'," said Kukawski.

During September, GOG.com has "one or two new announcements" to make, and believes "the next couple of months should make fans of classic games really happy".

"Our team was at gamescom and they came back tired but very happy, if you know what I mean! Aside from that, our development and design team is working really hard on another update of the service itself that will bring many useful features and will improve the GOG.com experience," he added. "It looks like a really great autumn/winter for GOG fans!"

Head over to the GOG.com website to find out more.