The aim of this challenge is to use a candle to burn through a water balloon, which should then extinguish the candle.
staves and sisal
To start, hang water balloons at various heights from the ceiling. Split your Scouts into teams and draw a base line some distance away from the balloons. Provide staves and sisal (or bamboo canes and rubber bands), as well as one candle and a match per team. The challenge is to make a pioneering structure such as a tripod, plus a long pole tied with sheer lashings, to reach the balloon from the base line. The structure should be used to hold the candle and position it beneath a balloon. Meanwhile the pole can be used move the structure into place and then to hold a match.