How about a cool Christmas tree made completely of pine cones? This one looks stunning. And it is so easy to make it. You will need a foam cone-shaped base. These ones are usually used by florists. Use wire to attach the cones onto the foam.
With pine cones you can make a cool wreath too! It will bring the festive look in your living room. Hang it above the mantel so it is the central focal item.
I love the shape of pine cones. It is so similar to trees. So, why not make a tiny replica of a Christmas tree? Just paint it in green an attach beads as ornaments. Do not forget the star on the top!