Design a Backyard Ninja Warrior Course

The design must be safe for adults and children and should be able to be assembled in weekend. Should be able to support 250 lbs hanging from the centre. Approximate dimensions would be 8 feet tall, 10-12 long and 3-4 feet wide. I can be built out of readily available 4x4" or 2x4" wood or similar and put together with standard wood screws. It could be put together with pre-cut and drilled metal tees or triangles as in the attached picture. That would be manufactured by a supplier. I should be a stand-alone structure that does not require holes in the ground. It should be able to be configured with multiple obstacles. Google Backyard Ninja Warrior course for ideas, or watch American Ninja Warrior show.