There used to be whole industries around making ropes for sailing vessels. Many of these ropes were made by hand. For a really cool Pathfinder project, make a big fat hawser of a tug-of-war rope. For that matter you can make rope in a variety of sizes for a rope bridge or for lashing together other camping structures.
It's fun and if you can get a good deal on binder twine, you can make quite a lot of rope for a fraction of the cost of buying it down at the hardware store.