Some people go so far as to fill their car tires, basketballs, soccer balls with pure nitrogen:
http://www.washingtonpost.com/wp-dyn...073100577.html
Maybe it has merits, but seems a tad bit silly to me. They claim to get slightly better gas mileage, but it's probably mostly because they're obsessing over their tires and filling them up more often than they would otherwise.
There was a thread on BF about a year ago where people were arguing about whether CO2 or Nitrogen, or whatever was the best thing to fill tires with. It went on for several pages and got quite heated. Finally somebody posted something like this:
I have discovered an ideal mixture of gases for pumping my bike tires. It took quite a bit of effort to get it just right, but it was totally worth it. I use about 78% nitrogen and 20% oxygen. The rest I haven't quite worked out, but 1% argon seems to make quite a difference. Luckily, I've discovered a natural source of this combination of gases, which makes it a lot easier to prepare.
Suddenly, everyone felt quite sheepish, and the thread died a peaceful death
