First things first, this is not shout in your face military survival skills, this is about primitive survival skills, going back to basics, becoming caveman (or cavewoman). Learn how to survive from nature by making fire starting with absolutely nothing, you make your own cutting tools, you get the material for cordage from the plants, make your rope by hand, make a bow, put your rope on it, create other items that are required and then you make fire with friction.
Making fire with friction is just one of the things you can learn, there are plenty of other things like boiling water in a cactus, learning about different types of camp fires, making shelter, making a spear and learning how to throw it, making traps and so on.
How about mixing primitive survival skills with exercise and turn it into a group challenge? Let me give you an example.
Two groups battle against each other in relays and team effort challenges, for example, running up a hill and back, making fire as a group, first one who gets fire moves to the next challenge, lifting and carrying heavy logs as an individual or as a group, crawling under and over objects, pushing or flipping tyres, throwing spears that you made, the possibilities are literally endless.