I noticed my nephew liked to pretend he was excavating fossils (crayons and coins) from my play-sand so I baked some clay bones for him to discover hee hee. It was surprisingly fun to do but I apologize to paleontologists everywhere for the... freedoms I took hehe. Also, I may or may not bury a unicorn fossil in our backyard. >_>
Edit: Uh-oh. I think he liked it too much. He actually thinks that, somehow, a real fossil made it into my room. hehe.