Neat game idea in kickstarter stage at the moment, hope it gets made. Google it to learn more, I can't post links.

1. About the Living: 30 Days to Survive
A free-to-play PC online multiplayer survival game!
Open World Environment populated by players and zombie
Introducing a new genre: 30 real days to survive
Intense Co-op Survival Experience
Real-time gameplay (every hour in-game equals one hour in real time)
Random Events! Player-made scenarios will unfold as players fight for survival

2. Customized Character Creation
Four unique professions.
Customizing everything from body type, skin color, hair styles, and much more.
Earn in-game currency to purchases new outfits, weapons, and supplies for your character

3. Playing the Game
Players will need food, water, and shelter to stay alive
Team up with friends or hunt others for their supplies
Huge open world with accessible vehicles and houses
Play as a Zombie and hunt down other human players