I've just been introduced to the wonders of persistent world, group minecraft servers, and competitive minecraft (2 teams, 2 identical worlds, spectators, a set of objectives, first one to finish wins), by one of my friends who runs the sticky piston minecraft server hosting http://stickypiston.co/
Quite intriguing what dynamics are at play and what people get up to on huge world.
Minecraft is very RAM hungry though. It's some monster server he's had to put up.
Any of you interested in my asking if he'd do a DC members special price? Dont want to waste his time