Tip the jug and pour out all the water.  Set it down and it magically refills itself! 

A new profile has been added with large vent holes.  This will make the trick refill faster. Thanks for all who made the suggestion.

Spoiler: Hold your finger over the tiny vent hole when pouring.  Let the jug sit for 10 to 15 seconds while you wave your magic wand.  This time is needed for the center chamber to refill with water from the outer chamber.  Tip: Pour the first one quickly.  Pour slowly for subsequent pours to make it appear to have more water.

Here is a video of the trick in action:

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