What you'll need:
Few playing cards
A plastic glass
What to do:
Take one of the cards and cut it across its length. Stick a tape along the edge of the half card.
Stick the half card at the back of a playing card. The card will act like a base to keep the glass.
Place the card on top of your table, making sure that the half card is facing you and not the audience.
Have fun watching everyone clap when you show them your anti-gravity glass!