Meet NinjaLine: a ninja training kit with 7 obstacles that can be installed between two trees to give you a challenge. Just string its 2″ wide nylon ninja line between two posts and hang the obstacles from carabiners. You get three 10″ monkey fists, two 16″ monkey bars, and two gymnastics rings to get started.
This particular kit has max weight capacity of 250 lbs. Costs $99 at this time.