I think a mafia server would be like the mafia gamemode. Loved that.
I think I'd like having some-kind of post nuke war with zombies would be cool.
Zombies outside
Air is toxic
only a limited amount of oxygen.
You have too stay inside O2 Zones
if you leave, O2 starts being used
when you go into 02 zone, it refills
zombies can rip off your o2 suit
survive this and you may be rescued
Something like that would be awesome