I have found a good use for those stretchable name tag cords that are used at most conferences these days. It is easy to make two holes on opposite sides, near the top, of a pill bottle. I then push the metal tips of the cord through the holes (from the inside). The tips pivot so they will not pull back through the hole, but I make sure by placing a small piece of tape around the outside neck of the bottle once I have the cord in position. Now I use nickels (about 5.5 grams each) to simulate different weights of bungee jumpers and collect data with the Calculator Based Laboratory (CBL) Motion Detector and graphing calculator. I usually tape an index card to the bottom of the bottle to give the motion detector a nice target. I have my students find the equilibrium height and then do a drop to find the maximum fall distance and recoil height for each mass.