I used to play Zombie Horde a lot, it was the mod which had only players as Zombies instead of bots. There was a map called boatescape_2 or something, which I absolutely loved because the entire thing didn't revolve around killing the other team, you could escape on a helicopter (Flying in the air amazed me back then) and go to an island that was safe from the nuke.
I wondered if there was a server which had maps which were all like that, so I checked out all the servers beginning with Z until I reached a server called ZOMBIE ESCAPE UK. It sounded fun and what's better was that it was situated where I lived. Without hesitation I joined the server and was pleasantly surprised. The community was really nice (Basically, there were no pre-adolescent American teenagers screaming down the mic) and I found it great because the rounds were pretty long but people rarely ever died, they just turned into Zombies. This meant that I wouldn't be killed early on and have to sit through 7 minutes of watching people run to the end.