To celebrate their fifteenth anniversary, Bohemia Interactive have made their newest game, Arma 3, free for this weekend only. In addition, Arma: Cold War Assault will be absolutely free to own if you download it before Monday, 10AM Pacific Time. All of these are available only via Steam.

In addition to these two delicious gifts, Bohemia’s entire catalog is currently on sale, with games like Arma II and its standalone expansion pack Operation Arrowhead selling as low as $2.59 and $3.99, respectively.

Other games from Bohemia on sale besides the Arma series include zombie survival/human depravity simulator Day Z, Take On Mars, Take On Helicopters and underwater puzzle game Fish Fillets 2, which is selling for a dollar.

The Arma 3 free weekend will allow you to play everything; multiplayer, scenarios and a sampling of the single player campaign until Sunday, 1pm PDT. The single player campaign was only just recently finished by Bohemia as a series of downloadable episodes, and consists of three of them: Survive, Adapt, and Win. Only the first episode will be playable in the free weekend version.

Should you find your free Arma 3 experience worthy of your money, the game is also on sale at a 40% discount for $35.99. The Digital Deluxe Edition, which consists of a soundtrack, maps, a game guide and Arma: Cold War Assault, is also available at a discount for $38.99.

Arma: Cold War Assault is perhaps better known as Operation Flashpoint, which Bohemia developed under publisher Codemasters in 2001. Because Codemasters still owns the rights to the Operation Flashpoint name, Bohemia renamed it to Arma: Cold War Assault when they re-released it in 2011.

As an additional bonus, Bohemia is allowing anyone with non-Steam versions of Arma 2 and its numerous expansion packs to redeem their CD keys to access the Steam versions of the games. Head over to the Bohemia Interactive Anniversary page for information on how to redeem your CD Keys.