I've recently gotten several packages that came with cardboard circles and decided to come up with creative ways to reuse them. The first was this Clock craft, that will help teach numbers, colors and time.
What You Need: A Cardboard Circle, plain white paper (2-3 sheets or enough to cover circle), construction paper, glue, scissor, two pipe cleaners
What to Do: Cover the cardboard circle with the white paper - one way to do this is to apply the glue directly to the circle then lay the white paper on the circle before cutting. This way you can line up edges and get full coverage. Cut out the numbers 1-12 from the construction paper or feel free to draw them directly on the white paper once it's completely dry. Glue the numbers in place. Use the pipe cleaners - or scissor if cardboard is thick - to poke a hole in the center of the clock. Fold pipe cleaners to desired length and thread them through the hole trying them together in the back to keep them from sliding out of place.