In the small but useful department, when you're in desperate need of a fire to stay warm, celebrate halloween in Detroit or fend off marauding hordes of zombies, getting a little chemical assist can be helpful.
Coghlan's Magnesium Fire Starter is a small 1x3x3/8 inch block of magnesium to help get you warm. You shave the block with a knife until you have a small pile of shavings about an inch in diameter, then you flip it over and scrape the strip on the back of the block to get sparks.
It's about as easy as it sounds, although you need a nice tidy pile of shavings for the sparker thing to catch. Or just use a match or lighter if you've got it. It's going to dull your knife, but if you're in that kind of situation you're probably going to be happy to make the tradeoff.