Posted On: 2010-02-21
Buy a bottle of soft drink for each boy in your den. Open them and pour contents into a large metal pitcher. Rinse out the bottles and let dry.
Set up a "re-fueling" station in your kitchen, complete with goggles, plastic apron, rubber gloves, and other "scientific looking" things. Make warning signs about radiation etc.
As the boys arrive, outfit them up and instruct them to "refuel" one soft drink bottle by pouring the mystery fuel through a funnel.