Big Contact Lens
This is a funny sight gag! The magician complains that his contact lens is falling out. As he reaches up to his eye a huge contact lens is removed or falls out. This is a real glass lens that measures three inches across.
This also makes a great base for my new spinning metal top. Since the glass is concave it helps prevent the top from jumping off of it once it's given a good hard spin. Also, being concave it helps increase the time that it will spin. See DJ's Top 10+.