Should take about 10-15 minutes at the most. (If you have all the materials.) My kid really liked this.
Step 1: Materials
First, get two stretchy bicycle tubes. You also need: scissors, and something to hang it from. (Monkey bars are the best-we used a wood ladder.)
Step 2: Cut!
Here is where you will use your scissors. First cut off the valves and discard.
Step 3: Tie!
Here's where the monkey bars come in. Here you have to tie a sturdy knot that will hold about 90 lbs if stretched.