Garden design by carolyn mullet: Plant stairs with succulents - this actually works very well, the succulents thrive on the heat from the stone in summer. If you periodically wash the stairs off with a hose, that's enough water for the plants.
Never thought of using shaving cream for clouds. Weather: Fill the cup with water. Put shaving cream on top for a cloud. Explain that when clouds get really heavy with water, it rains! Then put blue food coloring on top of the cloud, and watch it rain.
Girl Scout friends: The Pumpkin Project. Open a pumpkin, add soil & water & watch the seeds already inside the pumpkin grow. Also links to other activities to teach about & observe the pumpkin life cycle.