I was amazed at how light and efficient these DIY stoves are too when I first learned about them. You might also want to make and test the SuperCat Stove.

Personally, I like that one better than the penny stove. I think it's easier to make, simpler in design, and easier to light.

There are lots of other stoves you can find to make here, as well as a lot of other cool DIY stuff.