I do kinda like the idea of an "always on" Death Match type game.
Set up server shards with a max population of about 30 people or so dump them into an arena and let them hunt each other down last man standing wins.
The game map would need to be large enough that remaining players can safely hide or evade the other players to the point where a single game can last more than a few days.
The trick is that your avatar stays active in the game even if you log out so you need to make dam sure you hide properly before you head off to work/school/sleep.
Of course the game would need some sort of director AI to realize "hey it's been a while since any logged in characters have met each other, I should generate some hazards to drive them into closer proximity.
And then the Werewolves attack.