Well, here's a peek at the sets I helped design and build for a church play. I had a pretty laid out plan for what to put in the scene, but had some free reign on the construction and layout.
Notice the rocks, I had some fun with them. They are masonite panels cut into "rock" shapes with Great Stuff insulation sprayed onto them for texture. I explain this as making rocks by de-erosive means. However, for anyone that may be contemplating this technique be warned, it works better when it's warm.