I was talking to one of my physics teachers about this!

“Now, I just have to find out how to get my hands on some of it.”

From the link right on the page (with notes added):

“SF6 (sulfur hexafluoride) can be prepared from the elements, that is exposure of S8 (sulphur) to F2 (fluorine). Some other sulfur fluorides are cogenerated, but these are removed by heating the mixture to disproportionate any S2F10 (disulfur decafluoride, deadly in large concentrations) and then scrubbing the product with NaOH (sodium hydroxide, aka lye, caustic and dangerous) to destroy remaining SF4 (sulfur tetrafluoride, corrosive, releases dangerous hydrofluoric acid when exposed to moisture).”

So you probably don’t want to get your hands on it that way, at least not without rubber gloves. ;)

Had some friends in high school that would purchase canned freon (vehicle AC recharges), and “huff” it to get the same effect….low, low voices.

“did you see the size of that chicken?” (a la young guns)

SF6 is the most potent greenhouse gas known, 22000 times as powerful as carbon dioxide. Letting just a pound of this stuff into the atmosphere has the same effect as running two passenger cars for a year. Please reconsider the “coolness” of this experiment in light of its environmental impact.

References:

http://www.epa.gov/highgwp/scientific.html
http://www.epa.gov/otaq/consumer/f00013.htm