darxus

You can make enough heat to make fire by rapidly compressing air.

"Fire pistons have been used in South East Asia and the Pacific Islands as a means of kindling fire since prehistory."

http://en.wikipedia.org/wiki/Fire_piston
http://www.youtube.com/watch?v=Win_t0xtcQs

I find this particularly exciting because it appears to be by far the easiest way to make fire that doesn't include anything difficult to obtain.

No ferrocerium or flint. And easier to use than a bow drill.


Thanks to perspicuity for mentioning it.