We have one of these and someone put a piece of a popsicle stick and wrote "Rock Concert" - Love Rock Art.Garden Trinkets - Awesome Ideas, Projects and Tutorials! Including, from 'instructables', this creative 'garden thing' project with rocks.
Use crayons to color different spots of bright colors on some paper. Color over the area with a black crayon. Cut out a shape. Use the popsicle stick to scratch out the black and reveal the colors underneath. or hang