Remove a thin pop-up greeting card from a flat envelope, and open the card to show that a 3-dimensional box has formed. Magically produce a solid ball from inside! Many variations are possible: explaining that you've placed a prediction inside the envelope, and then produce a ball of the same color that has been chosen freely by your audience. Use the enclosed capsule to produce a piece of candy or a finger ring, and hand out the item as a gift. You can also produce a written message that will delight your audience.