Now that summer is drawing to a close, I'm building up my file of fun after-preschool activities to do with the kids in the afternoon. The rules require that the activity be fun, simple, inexpensive and relatively easy. A new friend emailed me about a fun way to create beautifully colored rocks using crayons.Blair of Wise Craft tells us that rocks with a flat, smooth surface work best. After you've taken a nice long walk with the kids and gathered your rocks, heat them on a foil-lined cookie sheet in the oven for 15 minutes at 350 degrees. While your rocks are baking, peel the paper off of the crayons you're going to use. Once ready, handle the hot rocks with oven mitts and have the kids draw away. The crayons will melt beautifully onto the hot surface. Just remember that the rocks will be very hot so make sure your kids know to handle them with oven mitts.