On behalf of many people who I think would really love having more players in this mod, here's an introduction to the mod.
Day Z is a zombie mod to the somewhat-known ARMA franchise which is currently in Alpha testing mode but still available to everyone for free currently.
ARMA is a 1st and third person shooter/simulator. This game is primarily a war game with server-hosted multiplayer for many types of missions; such as Co-op, Player vs Player, Player & AI vs Player & AI, and so forth.
Day Z, as described earlier, is a mod which adds zombies to the game and takes away the military aspect of ARMA leaving the best Zombie Apocalypse Game and may I even go as far as saying Simulator I've ever seen. Day Z uses a continent of the Operation Arrowhead standalone game, a continent named Chernarus: a 225 km2 area for players to play.
A video speaks for a trillion words:
Regular DayZ gameplay, zombie encounter. (keep in mind zombie numbers have been strongly vamped since this.)
There's many aspects of the game that truly make it seem like survival and ultra realism; temperatures, illness, fully portrayed day/night cycle, hunger, thirst, vehicles, repairing, gas, and more to even come such as drinking your own piss at absolutely necessary conditions (I know, incoming Bear Grylls memes.) There are also items to help you during the long darkness for you night gamers such as flares, chemlights, campfires (to even cook meat from animals). There's also the option to hop on a different Region server though pings may not be as low as they normally might be.
Since the release of this game, Combined Operations (30 USD on steam, includes both ARMA 2 & Operation Arrowhead though I run Day Z with regular OA + the free version of arma 2.)
Though it's kind of an old game and ARMA III will be coming out soon, the graphics are still very demanding, hell I barely could play it on low settings with my old HD5750.
Here's some links for those of you who want to buy it/learn more;
(You can always watch a couple more videos about the game if needed.)
Official Mod Website: DayZ Mod
DayZ Wiki: DayZ Wiki
How to download/install Day Z: How to install DayZ - DayZ Wiki
Combined Ops(Includes full version of ARMA II & Operation Arrowhead): ARMA II: Combined Operations on Steam
Official ARMA 2 Website: Arma 2 Official Website
If you have any questions, feel free to ask me via this thread or pm I'd be glad to answer them.