Navigate the Obstacles to get the keys
Some furniture / other obstacles - less obstacles can increase the challenge
Torch (head torch if you want to make it easier - hand held if making it more difficult)
Set of Keys (or other noisy object)
Place some barricades (tables / chairs / etc...) out in the room for the attackers to hide behind.
At one end place a chair facing the barricade with a blindfolded scout armed with a torch, put a set of keys (or bell, other noisy things) under the chair.
Scouts started by a leader at the other end of the room (which should be in very low light) must quietly navigate the barricade, by moving, tunnelling, climbing as necessary then creep to the chair and grab the keys.
The scout on the chair should be listening out for movement and highlighting where they heard it from using short bursts of light from the torch.
They then must get these keys back to the start point.
If hit by the light at any point they must return to the start point. If carrying the keys at this time they must leave them at the point they reached.
Leaders may choose to catch people themselves if they think they are being too noisy. (I.E. running through the course.)