Welcome to Chernarus. A 225 km2 open world post-soviet state and one of the areas hit by a new and presently unknown infection which has wiped out most of the world's population. You are one of the few who have survived and now you must search this new wasteland in order to fight for your life against what is left of the indigenous population, now infected with the disease.
Go Solo, team up with friends or take on the world as you choose your path in this brutal and chilling landscape using whatever means you stumble upon to survive.
Basically a zombie survivor sandbox game set on the huge Arma2 map. You can kill or team up with other survivor, loot equipment, explore, repair vehicles with part found around the world etc... The most amazing thing in my opinion is that it's a one man mod and the world is persistent, like an MMO. When you die you lose all your equipment and respawn somewhere else.
This mod requires ArmA II: CO to be played
More info at http://www.dayzmod.com