Fill a wide, shallow tray or storage box with sand. Bury small plastic dinosaurs in the sand, along with plastic bones and fossils. Give the children trowels or spoons to "excavate" the dinosaurs. Let them carefully brush the remaining sand off with a small, dry paintbrush. Explain that fossils must be treated with care because they are so old.
Set up an art station with dinosaur coloring pages and crayons, markers or colored chalk. Encourage the children to be creative while coloring the pictures. Set out modeling clay for children to form their own dinosaurs.
Draw or print out pictures of several different dinosaurs. Cut out and laminate the pictures. Divide them into sections with interchangeable body parts. For example, cut off the heads, tails and feet of each dinosaur so the children can mix and match pieces of the pictures to create their own silly species. Let them name their creation, adding "saurus" to the end of the name.
Use a latex fossil mold and Plaster of Paris to help children create their own fossil replicas. Commercially-made molds are available through educational supply stores and websites.
Read age-appropriate books about dinosaurs. Teach children about the most well-known dinosaurs, like Tyrannosaurus and Brontosaurus. Have them understand basic facts about dinosaurs, like what they ate, how big they got and why they are now extinct.