A Steam news announcement says that users will be able to play Arma 3 completely free this weekend, and if you decide to buy it you'll only pay half price.
There's nothing much more than that really, other than you should head over to the Steam store page to download it and see what you think.
I guess in the interest of keeping this news piece more than a glorified tweet, I'll give you some details on the game. Arma 3 is an open-world tactical shooter from Bohemia Interactive, the creators of the Operation Flashpoint games. Remember those? Think less CoD, more Battlefield, but with a focus on way, way more simulation and realism. Basically, it's free for a couple of days, and I've heard it's pretty good, so just check it out, you've nothing to lose.
The free offer ends at 6pm BST (10am PT). Have a look at the trailer below.