While watching the dolphins at work, I finally had my camera in hand and caught them doing their bubble rings on film. I first witnessed this phenomenon over a year ago when one of the large females (Bailey, I believe) at work started doing this. Over the past year, I have seen a couple of the dolphins playing with bubble rings. They create everything from small rings, to large ones the size of a hula hoop, and if you're lucky, you'll catch them making a helix, sometimes very large. They are very skilled at manipulating the rings, changing their size, and sometimes manipulating the shape into a sort of 'infinity symbol' loop type shape.
Here is a shot of one of the younger ones.
It really is the most amazing thing to see.