FIREPLACE: Cut a hole in the front of a box as shown for the firebox of your fireplace. Fold the two sides back. Cut a piece of cardstock and glue against the top and back of the folded-back pieces to complete the firebox. Cover the front and sides of the fireplace with spackle. You can texture the spackle and let it dry for one look. Or you can cover the wet spackle with model train or aquarium gravel for a stone look. Add a wooden mantle (stained or painted). Paint the firebox with a wash of black paint (paint mixed with water) to give it a used look.