Just roll it away on the ground like a bowling ball to wind it up.
Step 1: Make first hole
Big 2 quart round Gatorade bottles work great.
Drill a hole in the center of the bottom of the bottle.
Any size drill you have handy from 1/4 inch to 1/8 inch is fine.
You can even use a soldering iron to melt a hole in the bottle.
Wear safety goggles.
Work on a proper workbench, not your kitchen counter like I did.
Step 2: Prepare the Cap
Put the cap back on the bottle and drill out the center.
Just like the last step you can also use a soldering iron to melt a hole in the cap.
Step 3: Build the Rubber Motor
Wrap a stack of 15 pennies in reused and recyclable aluminum foil, and duct tape this weight to the center of the rubber motor.
Stick one end of the rubber motor through the cap hole.
Using a wire or string, pull the other end of the rubber motor through the bottom of the jug.
Step 4: Install the Motor
Use toothpicks as cross-pieces on the jug cap and bottom to keep the rubber band from slipping back into the jug.
Adjust the two ends of the rubber motor so that the weight is centered from side to side and top to bottom.
You may have to pull the rubber band ends back and forth until this is right.
Now duct tape the rubber bands and toothpicks to the cap and bottom of the bottle.