Evil Mad Scientist says we can do a easier version of the “floating on nothing†trick featured in the hexaflourid post.
You can actually do a version of this trick at home, using stuff that you either already have or can get a the grocery store: You can blow bubbles and float them-- apparently in mid air-- atop a layer of carbon dioxide; a not-very-exotic heavy gas. You'll need a big pot, pan or storage bin (made of plastic or metal), some dry ice, and bubbles.
Complete instruction are posted, plus a video of the trick in action. Now, if we could get hold of some Zubbles, this would be just too cool! http://www.evilmadscientist.com/article.php/bubbles
--TwoDragons