Fire up Steam to take advantage of a free-to-play weekend for the turn based strategy to rule them all, Civilization 5. The Firaxis Games epic will be free until 1:00PM PDT on June 9, in celebration of the upcoming release of expansion pack Brave New World. 2K is also offering 75% off the entire Civilization franchise until 10:00AM PDT June 10, on Steam and beyond. If you pick Civ 5 up on sale, you can carry over your saves from the free-to-play weekend, too. Brave New World is available for pre-order, by-the-by, at 10% off.