Who remember's the 1990s and playing Minesweeper? This is a real-life version!
Map of local area, turned into grids - printed for each small group of scouts.
Another map, with bomb & numbers added, printed for each leader.
Each group of scouts goes to a place on the map, and if they believe it is safe, they tell you they know it is safe, and you tell them what is there - which will either be a bomb (in which case, they lose a life), a number (you tell them the number), or a blank area (then you tell them the coordinates of the entire blank area, and their adjacent numbers).
The scouts then have to wander around the neighbourhood, working out where the bombs are. When they know where the bomb is, they go to the cell and "mark it as dangerous" (by telling you). If they get it wrong, make a note of it.
At the end of the meeting, see who found the most number of bombs, and the winner is the one who lost the least lives and/or number of incorrect bombs.
We talked about landmines at the start of the meeting to raise awareness.