Sniper Elite just announced a super awesome Nazi Zombie Army Standalone Expansion with up to 4 player co-op. Awesome game and one of my favs from 2012. They have a 4 pack available for pre order and I am looking for three others interested so I can host. Tentatively waiting to see if Gamersgate is going to carry it to see if I can get it even cheaper there. PM if interested.

http://store.steampowered.com/app/227100/