1. Fill a cup half to three quarters full with water.
2. Wet the lip of the glass with water and place the card on top of the cup.
3. While holding the card in place with one hand, use the other hand to flip the cup upside down.
4. Continue to hold the cup upside down and remove your hand from the index card.
5. To flip the cup right side up, hold the index card to the cup and quickly flip the cup.