Custom room game.
Both teams are fighting over a castle.
Objective
Reach the top of the tower and claim it by pressing a button.
Hold it, until timer runs out.
When button is pressed teams' spawn points switch, defending team's countdown is started/resumed and attacker's team paused.
Attackers
Re-spawn immediately after hit in the area surrounding castle. Armed mostly with quest swords and shields fight their way through the castle to the top and press the button to claim castle.
Defenders
Re-spawn inside the castle with a few seconds delay. Armed mostly with ranged weapons try to fend off the attackers, until their timer runs out.
Custom map examples
Somewhat different rules but same basic idea: