A little more complicated, but the most fun I've had with a scenario battle was at Rag 22, II.
In the middle of the field there were three large rope circles, with a regen on opposite ends of the field. Sitting on either side of the three large rings, there were groups of voulunteer drummers. At the start of the battle, timed at Five minutes, the drummers were told to start a very slow beat, increasing the tempo slightly every minute, for the Five minutes, until the last 30 seconds, at which time all drummers are told to drum as fast and loud as they can until the end of the round.
At the end of the music, and 5 minute timer, all fighters on the field take a knee, (dead clear), whichever team has more team members ALIVE within the circles boundaries at the end of the battle controls the circle, whichever team controls two circles wins the game.
I had a great time playing this game (even at Ragnarok) because it's a regen battle with a time limit, constant spawn-ins, and incorporates battle strategy etc. Also fighting to drums is **** gnar.