Another great camp type craft that kinds and adults enjoy. For a Hollywood themed week we made square and round stone with hand prints so that every kid could feel like a star. Otherwise we used a collection of shapes from styrofoam vegetable trays, pie pans, and other recylced molds lined with plastic (cut up garabage bags or shoping bags) filled with wet concrete mix and decorated with sticks, stones, sea shells, glitter, pebbles, and inprints.
The concrete needs a couple days to compeletly set before removing from mold so not to risk crumbling.
(Hope to add better instructions soon!)