I purchased 14 pipe insulation tubes from Lowe's and cut them in half. Each person got two halves, although they could pool theirs together to create a longer run. Each roller coaster needed to have one loop. The kids could work in groups or individually.
This was a fun, easy program to do. The kids spent 45 minutes building and would have gone on for longer if we'd let them. I was amazed at their perseverance. We did have two teen volunteers at each session to help the kids and one dad even stayed to enjoy the fun. We let parents/caregivers come in five minutes before the program ended so they could see what their kids accomplished.
Here are pictures of the fun.