This is magic that defies all the laws of nature.  
You are seen to fill a small vase with water, cover it with a piece of stiff card stock and invert the vase.  Let go of the card and the water does not flow out.....  
A scientific phenomena?  
Of course!  
 
Everyone knows that the card stays due to air pressure.  So where's the Magic?  
 
You now put the card stock over the mouth of the vase again and turn it over, only this time you remove the card stock without the water flowing out!  Replace the card and turn the vase right side up.  The water can now be poured out of the vase!
 
Nice effect and easy to do.  Instructions and performance tips included.