Helium flight

Not for children: Take a bic lighter. Grasp a party balloon helium tank between your thighs, and put a black garbage back over your lap, and thumb the nozzle open. Use only non-flammable helium or even plain "air." When the bag inflates, grasp the edges tightly with your outer feet and twist the top part into a Higgs funnel. Now make a small spout at the top for the air in the bag to escape and enter the vortex. Light the lighter and hold up to the "spout." The excess air will "burn upward" with the helium, creating a brief but intense upward drag all around the perimeter of the bag. Careful not to light the bag or anything else and let go the bag with your feet: It will rise with a force of about 75 psi. Anything attached to it will rip away, including light furniture or picnic supplies.