Using pebbles and other drift items on the beach, make a picture.
A pebble beach (other types of beach are available)
Vivid imagination !!!!
File upload for inspiration !!!!
Let your cubs roam the beach collecting items they want to use to produce their art !!!
Give them a theme, or just let their imaginations run riot !!!!!
Take photo's for posterity.
This can be up or down scaled to suit both ages and time scales. Get the leaders involved to see who can do the best art !!!!