Building shelters and trying them out - great on a summer camp
Woodland and any other resources you want to give them e.g. bin bags
In groups they should build shelters within an allotted time with whatever they can find and any resources you wish to give them. Specify how many it should shelter. When the time is up leaders test the shelters with water and see how wet the inhabitants get and score them accordingly. Add additional marks by asking them to camouflage their shelter. You could build a scenario around it such as a secret agent on the run who needs to hide and build shelter. This could also be used in a Group Camp when Beavers have to be sheltered - it gets them involved when otherwise they may feel left out etc.