Ok, how about a variation on the Kelly gang idea....
All players divided into 2 teams, one "Kelly Gang" one "The Law".
We set up a new world for the event (so everyone starts with nothing and has no prior knowledge of the terrain). There is a small town and a train (I like that idea), each with a chest (or more) of random treasure (more weapons, food etc.).
There is a pre defined area for each team (equal distance from the town), in which there are chests with some basic building supplies, armour and weapons and a bed. When we start, each team has 30 mins to build their fortress however they wish, with the building materials supplied (and perhaps with additional supplies they gather themselves if they want to go punching trees?).
In the centre of each team's defined area is a chest with a special piece of treasure they have to guard (essentially a "capture the flag" situation). This chest (and it's contents) can't be moved, buried or blocked off - it must be able to be reached if an opposing team member makes it through the fortress. You can make it difficult to get to (by way of a maze-like fortress or good defence preventing people getting into the fortress), but it has to be reasonably easy to obtain, and no death-traps.
The idea is to build a good enough fort that it's difficult for the opposing team to get in (should we make it that no blocks can be destroyed? for that extra challenge of not being able to just pick your way in?). So you try and prevent the team getting into your fortress if you can by having good defence (and/or preventing them getting away with the treasure, by killing them before they get back to their fort and returning your treasure to it's chest)
Then when 30 mins build time is up, the game is on - Each team needs to both protect their treasure and go searching for the other team's treasure, and optionally, find the treasure in the train and town and take it back to their fortress. So each team needs to work as a team, and decide who is going to defend their treasure and who goes to raid.
The winning team is the team that is able to bring the opposing team's treasure to their treasure chest. If the town/train was also looted, then that is bonus treasure to be divided up among the team who has it at the end (that treasure may change hands or be used during the game).
Last edited by Obsi; 22nd January 2012 at 08:38 PM.