Bubble rings
 

Pretty fucking cool
http://www.break.com/index/pool_bubble_rings.html

that was pretty fuckin cool

I can blow smoke rings. I'm wondering if it's the same concept to do it. I have a pool at my school and I'm going to try it.

It's not... lol I saw a video of this a while ago from some reef diver dude... I tried it for a while in a pool I couldn't get it to work...

I only tried a couple times though.