The magician shows a pitcher of water (you supply your own pitcher) and an antique milk bottle. You pour the water form the pitcher into the milk bottle. Place the pitcher on the floor. The magician covers the top of the milk bottle with a playing card or his hand and turns it upside-down. When the card is removed the water stays in the bottle.

At the magicians command the water starts gushing out of the bottle. Not tinkling, or slowly leaking, but GUSHING! When the magician commands, the water completely stops, and then he starts it again!

It appears totally impossible!