It takes something truly exceptional to be both impressive and completely useless, simultaneously : Let's face it, smoke rings are cool and sometimes mysterious. (Maybe just not 5 min. and 31 seconds worth of cool and mystererious). Amaze the kids and without lighting up! (zerotoys.com YouTube video) Naturally occuring vortex rings are even cooler. The inventor in the first link, (Aussie Peter Terren of the previously mentioned tesladownunder.com) shows more on vortex ring launchers) and has also recently discovered both YouTube and MeFi. Keep up with his latest geekiness on his What's New page.
A lightning bolt created a beautiful smoke ring in the sky the other day. It resembles of Mt Etna's and other volcano's beautiful rings. Nature at it's best.