If you have a lot of soft drink cans lying around — or are just looking for a cool project to work on — this mini foundry can melt metal and doesn't cost very much to build.
Melting things is fun, and this guide and video from Grant Thompson — The King of Random — gives instructions on how to build your own backyard melting machine. You need a few different buckets, some plaster of Paris, and some sand. You'll also need a strong steel cup for the crucible (Thompson uses the bottom half of an empty fire extinguisher).
Once you have set it all up, you can melt soft drink cans and other metals, then recast them in your own moulds. It's a pretty extensive project, and it requires some common sense and safety, but the end result is awesome. For a more thorough, step-by-step guide, check out the link below.
How to Make the Mini Metal Foundry [Instructables]