Here's an idea. Players vs. NPCs and monsters.
Something similar to the town raids on OSI, but on a much, much larger scale. Balrons invading west brit. Ancient Wyrms invading trinsic in the hundreds. Pull in some higher end AOS monsters to invade random wilderness areas. Push that RAM to the max.
Force players to work together. Healers res kill, shopkeepers attack buyers, and tamed pets attack owners at will. Faction guards turn on their own faction members. Every already spawned animal and npc attacks any player on sight. Sea serpents flood the oceans, making boat travel near impossible.
With all that disable recall, gate travel, and ethies. Should make for a very interesting weekend.
To balance this out for the players, reagents are not required, mana replenishes in seconds, casting speed is increased x2 (this includes npcs/monsters), wrestling does good damage, and the equipment stones hand out perfect silver vanqs.
Try to outnumber the players 5 to 1 and this could be some fun. Add a goal to this: If in the end, let's say Sunday 8pm, there are less than 1000 players -or so- online (or maybe our total kill count is less than the amount of total accounts, forums and hybrid combined), the monsters win and we get punished when the server goes back to normal. If the players win the war, we get rewarded.
Those are some serious odds. Let's just hope the server could hold the load.
There would be mad pvp out in the woods and maybe you could even turn of murder counts for the weekend to push this even further. hehe.