Original material copyright Jonathan Woodward.
Some disclaimers apply.
Hot-air balloons are not rated for use at altitudes of greater than 200 centimeters. Dynamite may adhere to some types of skin. All catapults and ballistae are manufactured by the Beep Beep Seige Weapons Company. Under some conditions, fuses may burn at 100x their rated speed. Trampolines may undergo unusual state-transitions when impacted at speeds approaching terminal velocity.