Use old rope for hanging tree swings or any other kind of swing.
You can also make a bracelet or necklace by burning the two ends of the rope together.
Tying various knots in the rope makes it a sort of dog toy. The monkeys fist knot can also be a good dog, and even cat, toy.
Using an old rope as a tug of war rope is another way to reuse old rope.
If you are not familiar, skitching is when you or another person are on a skateboard, skates, etc... and are holding a rope and being pulled by something ...