about 300 feet of string.

Cut about 100 pieces of string of different lengths - from 6 inches to several feet long.
Hide each piece of string before scouts arrive.

Stand in patrols.
Explain that you've hidden pieces of string, pointing out a couple of obvious ones.
The object of the game is for each patrol to find and tie together all the strings they can, to create the longest string.

The patrol with the longest string when time is called is the winner.