This is the first part of my server's PvP complex. It is a relatively simple flat circle encased in a glass dome at surface level. I did however add a fancy feature - ready rooms. In essence, they make sure that all the players are ready to fight then release everyone at once and do not allow you to back out of a fight. It also allows for more than two players to be released at once. It also has some fancy-schmancy viewing areas colosseum-style.