as penguin said, use an info_landmark. Also, it would be best if it wasn't arena. It takes forever to kill people, because people travel too fast to reliably hit them with any weapon, and so someone dying can have to wait for a long, long time to respawn. Also, have some health kits and ammo packs. They would actually make the game go faster, because i found it was very easy to hit people directly above/below you, and people could maneuver themselves to be above people going for healthkits