Summarize this article:

A safe and easy option for creating an obstacle course is to make use of inflatable obstacles.  Since these obstacles are inflatable they pose a low risk of injury and can add an appealing and lighthearted feeling to your obstacle course.  Check your local businesses and services to see if any nearby vendors offer inflatable obstacles either for sale or rent.  Most inflatable obstacles are designed with children in mind. Inflatable obstacles are easy to place, requiring little to no assembly. After you have your obstacles and their arrangement planned out you will need to acquire the materials that will be used to create the obstacles.  The materials you need will vary greatly depending on what you have planned for your course.  Look over some of the following ideas to get you started:  Hula hoops can make great markers for jumping or agility obstacles. A simple board can make a quick balancing beam. Hay bales or couch cushions can make a fun jumping obstacle. Small sport cones can outline the obstacle course or be obstacles themselves. Having assembled your obstacles you can begin to place them according to your obstacle course layout plan.  Place the obstacles where you planed them and evaluate their position before opening up our course to others.  You might find that a planned location for an obstacle doesn't work well.  Don't be afraid to make changes. Try doing the obstacle course yourself once you've built it to evaluate how well it works. Once you've built and tested your course it's time to open it up to others.

Summary:
Consider inflatable obstacles. Gather materials. Place them according to plan.