Sirsun
Scarcely Lethal Noob
Maybe not in normal maps with normal respawn times, but I feel like adding the option to temporarily enable friendly fire in non-serious servers could make for some fun intermissions. You could maybe make it so the duration of the friendly fire, if it passes the initial threshold to even be enabled, is determined by how many of the people on the server agree to want it on. So every 10% above the threshold adds 30 seconds.