Scouts are briefed that they have been in a shipwreck. After washing up on a desert island they have to plan their survival. In patrols they put together a rough plan/ideas to survive. Good to use after practicing/teaching survival skills to ensure scouts have picked up on survival skills.
Brief scouts: Along the lines of "you've been in a shipwreck, after washing up on a desert island you now have to survive until you are rescued" The exact situation can easily be changed such as things to find on the island, things salvaged from the ship and the proximity to shipping lanes/flight paths. Things to consider are Water, Food, Shelter and rescue. Its surprising what techniques individual scouts come up with, a wide range of water collection/hunting/shelter and signalling techniques.