Macro Photography on the Cheap (film camera or digital). Reverse Ring tags and a roundup discussion on Flickr. All you need is an SLR body (scratch that: you can even do it with a point and shoot) and reverse ring for your camera mount, and a lens whose filter size matches the reverse ring (doesn't even have to be the same mount as your camera!). Or, make one from a body cap. How/why it works, tips on shooting reverse macro, and even a podcast on the subject. It's even possible to do EXTREME closeups. Come to think of it, why not try this with video? Now, need to get some light on your macro subjects? Make a cheap LED ring light, or go low tech. Make tons of more stuff for your creative photography needs at DIY Photography.
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.