The Altoids Tin kit is a DIY classic. I'm almost nostlagic for the early days of the make/hack/indie craft blogosphere, where it seemed like every week, there was a new project and collection of stuff you can smush into one of these ubiquitous containers.
But, throwback-ish or not, it's also a darn good project, and something to consider keeping anywhere you might need it: your daily go bag, your glove compartment, your camping gear, etc.
Wes Siler of Gizmodo says,
Tiny, light and infinitely transportable, this affordable little kit might save your life in an emergency. Here's how to build your own mini survival kit and how to use the stuff in it. Why Altoids? The tins are universally available, well made and designed to keep the stuff inside them intact and safe from crushing. With a little work, you can even make them waterproof. They're also designed to ride in a pocket or glove box, under the seat of a motorcycle or even on a knife sheath.
You can go fancier and build a kit in a small Otterbox waterproof case, but the whole idea here is to create something small enough that you have no excuse not to carry it and cheap enough that you have no excuse not to make one. The items...[are] small, light, works-in-a-pinch stuff, intended to give you a diverse level of extra capability should you find yourself stuck somewhere with nothing else to rely on. The kit will work best when paired with a rugged survival knife.
Check out the how-to in full at Lifehacker: How To Build Your Own Altoids Tin Survival Kit