I met a girl in an airport once who is making a fortune marketing and selling oxygen for commercial use, of the high end kind. Had to go through a grueling FDA approval process and everything. It's so bizarre. Her big idea came from watching a documentary on the healing powers of hyperbaric chambers in the chronically, acutely ill in Canada. Some of her clients now include exclusive hotels, who offer it to their guests as a means of treating jet lag, for one.

And yes, she's for real. I googled her later. ;-)

Also handy for getting the charcoal in the grill up to temperature more quickly...

Actually, there is a reason for them in Japan (other than the smog that suffocates the whole Tokyo area). They sell them all the way up Mount Fuji, since the air gets a little rarified as you ascend the rather gentle slope. With a supply of oxygen, even the very old and very young can make it to the summit. (It tops out at about 12,400 feet).

One of my friends still has his cane and his (now empty) can of oxygen from his trip up the mountain; he said there were hundreds of people walking up to the summit on the day he went, and many of them had a can with them. About half a million people climb the mountain every year (during the summer).

Good point; I'd forgotten about the traditional walk up Fujiyama. This might be salable stateside, were there anyone actually walking on the mountains.