The L4D Blog has posted a new featured community map. The landscape should be familiar for most because it’s City 17 from Half-life. But instead of fighting Headcrab zombies you will be fighting your way through hordes of L4D style infected zombies. Valve will be hosting this map temporarily on their official dedicated servers, all you need to do is download the map. Valve posted the following instructions.
Double clicking the vpk should install it but you can also copy the vpk to \Steam\steamapps\common\left 4 dead 2\left4dead2\addons Either way that is where the vpks need to end up.
Start up Left 4 Dead 2.
Choose to play online and any available game/lobby in your area will show up. Or you can create your own game and choose addons and select City 17 for the campaign.
You can download City 17 here.
*Poster taken from L4D Blog