This was featured on Rock Paper Shotgun a while back
here.
It is out of beta now and free for everyone to join.
Basically it's a browser game where you and 39 other strangers (or you can bring 4 friends along in a coalition) are dropped in a random town somewhere in the post-apocalyptic desert wasteland. You have to scrounge around outside looking for materials, water, food, weapons, shopping carts, drugs, booze, anything useful to help survive every night against the zombie horde.
A few neat things it does that other browser games don't is that survival heavily depends on the citizens of the town working together. There are, however, also ways for your fellow citizens to subvert those efforts for their personal gain. Whether that is stealing from the town bank to improve their own homes, stealing from other citizens, etc. If you are caught however, you may face banishment or worse if your fellow citizens lodge 8 complaints against you.
I've been playing it for a few weeks and it's the only browser game I've played for more than 2 days. I must say each town really feels different depending on the motives and participation of your fellow citizens.
http://www.die2nite.com
