For this game you need two ropes to represent the banks of a river. The goal is to have the group cross the river.
Give the team six carpet squares (or something similar) to use as "rafts". Each raft can only support one hand and two feet at any one time. Any more than that and it will sink (meaning a leader takes it away and it's no longer available to the group). If a raft is left untouched for more than a few seconds, it floats away (again, have a leader monitor for this and remove any rafts). If anyone in the group touches the water, the team must start again.
The game sounds simple, but it's great for team building, as it requires everyone to participate and contribute towards the goal.