I've GOT to start taking pictures! I made a rock out of Polymer clay as part of a "scavenger hunt" Christmas present, and it turned out really good! The idea was for the "rock" to be the final item in the hunt. It was hollow with a removable bottom and hidden inside was a gift card. Ended up being about the size of a small canteloupe (sp?). I used some craft wire mesh and formed it into the rock's shape, then started adding the Polymer clay. If you're not familiar with Polymer clay, it's an oven-bake product, though not actual "clay." It's great for small craft projects, and was good practice for making bigger rocks (cement) later on.