H2O by Sandro Loporcaro

Here's one that crosses the line between illusion and reality. You see everything, so it must be real, right? 

Show an empty glass, and then fill it with water or other liquid. Place a large playing card on the top of the glass. 

Now turn the glass upside down, with the large playing card still underneath - the card adheres to the glass and doesn't fall to the ground! Remove the card, and the water now remains suspended inside the glass -- this looks incredible! At your magical gesture, the water finally falls down from the glass. 

No external gimmick, use any glass. Simple and clean. 

Download the video and learn how to amaze your audience.