Burning wood for heat has several advantages: it's cheap, it burns hot and it's relatively better suited to places that are off-the-grid and rurally located. But some rightly argue that wood-burning is sustainable only if some -- not everyone -- is cutting trees down as firewood, so we were pleasantly surprised to come across this idea for making your own burnable firebricks -- out of recycled newspaper!
Seen over at Survivopedia, a "prepper" site, paper log bricks could be a major help during a major disaster, when firewood may be scarce. Here's the basic run-down: recycled paper is either shredded or kept whole, and then moistened and mixed into a pulp, and either rolled or molded into forms using simple things like a cake pan punctured with holes to let the water out. After properly drying them, the paper bricks are ready to use; they are dense like regular firewood and require kindling to set them alight.
For the full tutorial, check out Survivopedia.