on what game is this server, and how to install it?

[HeArTBeaT]

title says it all LOL 

[xpr0legendx]

Gmod, you can download it on steam.

[Guest AleksCore]

http://store.steampowered.com/app/4000/

[Damien]

Here it is: http://store.steampowered.com/app/4000/​

 

You will also need css for textures (though they can be found by looking for CSS textures addon on google).

 

Edit: Ninja'd, DAMN you alex :<

[Knul]

€9,99 ?! Ain't nobody got time for that, boy..

[Guest AleksCore]

$6 here, I can buy it for you