This is a post on the 神流アトリエ日記 blog about a "rocket stove." I saw one of these in a 現代農業magazine today, and came home to research it a little. Very cool idea for several reasons.
1.) It's cheap to make. A drum can or two, some stove pipe, bricks, mud, gutter tiles, and some concrete, and it looks like anyone could make it.
2.) You can burn any size wood in it.
3.) It is useful for heating as well as cooking.
4.) It doesn't burn fossil fuels.
ロケットストーブ作る | 神流アトリエ日記（３）