I remember when I had a LAN party with three of my buddies, and we spent all day collecting cash from properties; business as usual. But when night fell - we suited up with armor, special weapons from the city planning department, maximum amount of M4 ammunition, and we bought TWO SWAT tanks. Two of us drove the tanks and two of us stood on top gunning with M4s. The drivers would use the water cannon to knock someone over while the gunner basically insta-killed them while they were laying down - helpless. Our kill/death ration was like 100/0. It was fantastic. We pay n' sprayed the tanks all night long.
I remember the only thing that killed us: Caturday. Let's just leave it at that.
I also remember gathering a fleet of four people, getting in a helicopter, and flying under the map - INTO the dual arena during a duel. Man, we unleashed hell on those two people dueling. Just allowing the rotors to protrude into the map - instantly killing them. We also broke the arena so they had to restart the server. Man, good times, good times. I'm pretty sure that's why it's not allowed anymore, and will result in a ban.