Valve's massive Steam Summer Sale may be the one garnering headlines and threatening the financial well-being of gamers around the globe, but it's not the only games store celebrating the fine weather with deep discounts on a slew of titles. kicked off its Summer Sale long before Steam's got underway, and today, the site's demanding more attention with a "24 hour Adrenaline Rush"--a full day dedicated to Flash Sales where games sell at steep discounts for short bursts of time.

And during the Adrenaline Rush, some of those games are free--but only if you act fast.

GOG kicked things off by giving away Omerta: City of Gangsters, an isometric "gangster strategy game" published just last year. The Flash "sale" is good until noon Eastern, or about an hour from the time of this writing. Don't fret if you miss out either: GOG says "That's only the first of the giveaways we have planned for today, so make sure to keep an eye out for more throughout the Adrenaline Rush day." The Flash Sales and giveawayd swap out hour-by-hour, though each individual deal stays up for several hours before cycling out.

Most of GOG's selection consists of indie and retro titles, but hey: Free games are free games, and all of GOG's games are DRM-free, meaning you don't need to worry about onerous copyright protection schemes or separate game launcher applications--at least not yet.