Have a Ball: This sugar-free card incorporates a bouncy ball for extra fun. Cut a large heart out of black or dark blue card stock. Use a craft knife (adults only) to cut a circle that's slightly smaller than the ball. (Tip: Make holes in scrap paper until you get the right size for your ball, then use that hole as a template.) Add stars and planets and your message with a gel pen. Insert the ball; it should fit tightly and stay in place.