Fun family entertainment for wizards of all ages.
A glass is covered by a large silk or a piece of cloth. It is picked up by it's rim, still covered, and thrown into the air. The cloth floats to the ground, but the glass has vanished.
All you need for this effect is a piece of stiff wire, curved in a circle the approximate diameter of the glass. Before you begin lay the wire ring on the table with three small pieces of clear sticky tape under it, face up at three points around the rim. Make sure it cannot be seen from the audience.
You can allow the glass and the cloth to be examined at this point. Shake out the cloth and spread it on the table with the center over the ring. As you lift the glass to show it to the audience, or take a drink, if it's full, press down with your other hand to stick the ring to the under side of the cloth. Pick up the cloth, with the ring now attached, and carefully spread it over the top of the glass so that the wire rests on top of the rim. Now you can pick up the ring and the glass together. As you pull the cloth toward you, let the glass drop out into any hidden spot that the audience cannot see. Be sure to have a safe, quiet place for it to land before you let go. A box lined with foam rubber below the edge of your magic table will do.
The audience will still believe the glass is under the cloth because the wire ring holds the shape. Hold the cloth up high and walk forward away where the glass lies hidden. With a sweeping gesture throw the cloth high up in the air. The glass will appear to have vanished as the cloth floats gently back to the ground.