Starting a fire without matches or a lighter.
I just thought some of you guys might like this one.
Take a chunk of extra fine steel wool and a 9 volt battery (the square one).
Rub the terminals on the steel wool this will super heat the wool QUICKLY.
Once it is sparked just blow on it with you're kindling over it and you're done. From start to Finnish 15 seconds. No more fighting with lighters and matches with cold hands.