When building an obstacle course for kids, there are many different obstacles that can be used. A wooden ladder can be placed directly on the ground for children to run through. Hoola-hoops can be hung with rope for climbing through. Old tires may be laid out military style. Nets and ropes can be used as climbing obstacles as well. Mud pits are fun obstacles for any age. Setting up a track for a bicycle or tricycle ride as part of the course is another idea that may be included. Large pipes make excellent tunnels to crawl though, and balance beams, especially if there is a mud pit on either side, are always fun.