http://urbandead.com/

I made an acount and its pretty fun. You can make a character that us to do a doctor or a fire man. I'm a cop. And you survived the zombie infection stage. Now you have to find useful items, and kill zombies. You can join up in groups(I'm not in one) and just survive. The only bad thing is that you get action points. You start out with 50 and get 1 more every half hour. And you have to sleep some time. I was asleep in the police station and 2 zombies broke in. Cut my HP in half and kill someone else. Then two guys came in and saved me. All while I was asleep. Check it out some time its tons of fun.