Imagine a swing set that has a waterfall coming from the large bar across the top.  Now imagine you swinging through it without getting wet.  It's hard to explain but pretty cool to see.

The video shows two people on the swings with water falling in front of them.  As they approach the water, a hole appears where they can swing through it without getting wet.

 

So why would anyone want to create something like this?  Well, according to Yahoo it was created for the 2011 World Maker Faire.  It's really just art.  But fun art at that!