Snakes and ladders
2 teams, and 2 extra competing players?
SNakes have to get their whole team to the bottom while ladders have to get their whole team to the top, preventing the other team from doing so.
Rising water to create a losing condition. A dying snake player will respawn at the top, a dying ladder player will spawn at the bottom, players will need their teams assistance to get back up.
Another idea is that the snake team has to prevent the ladder team from reaching the top, as the snakes in th board game version of the game have no real intention of reaching the bottom of the board, they are just douchebags who dont want you to get to the top. With this scenario there would be a time limit which would count down and the ladder team would have to get to the top in that time.
We need to brain storm some ideas of what will actually be the mechanisms represented by snakes and ladders which allow the teams to move.
The first idea is that the ladder team has a collection of different size laddders which can be moved to where they are needed. By doing so the team is able to move up the building. The snakes team is able to move the same ladders and drop them back to the ground. The ladders team has to reach the top before the building collapses or another limitation.
Building outside?