The Rocket StoveOne stove design that can be very useful in developing countries and survival situation is the Rocket Stove. A rocket stove uses the principals of a chimney to build a very efficient stove that runs well on scrap wood, twigs, and other easily collected materials. These videos from Youtube show how to construct a rocket stove from simple materials like bricks or cans.
This first build uses bricks to create a rocket stove. It's an easy to see how this stove is easy to start and feed using sticks and kindling.
This second rocket stove was created using cans and small pebbles. These sorts of stoves provide portability. One note of caution, while traditional cans are usable for a rocket stove, galvanized buckets and cans release dangerous zinc fumes when heated. Since these zinc fumes are toxic and will contaminate foods, don't use anything galvanized for stove construction.