There are some good ones, however I believe I have found the worst one. 'Twas a while back, some Trench TDM whose host's name started with an L, but I forgot exactly what it was.
The host was AFK at first, and it was alright, but when he got back, he dug a hole in front of one of the bases, put a JVS door he didn't even bother to modify except to say any non-admins walking in will be banned, and called it the admin room.
It was really easy to walk in there without knowing, and he replaced his own weapons, which everyone had a spear, a bow, and a sword, with a shotgun. There were also a bunch of random tanks lying around.