Yay, I am so excited! My air plants came yesterday. Not to be confused with "air ferns" (which are also interesting, if nothing more, just to read about even).
Tillandsia are one Air plant variety. Tillandsia are Epiphytic (do not root in soil; grow upon something else for support) Bromeliads. There are other epiphytic air plants: moss (Spanish moss), ferns, lichen, fungi, algae... and even including some lovely orchids, and the parasitic mistletoe.
Air plants are commonly found attached high up in the air, attached to their host. Those of you from FL probably see these daily! I know I have seen a multitude of them there before.
I have been affixing the plants to some more decorative and functional displays. Yes, naturally, some of these involve seashells. :P