Have you seen Rough Science? It's a BBC/Open University program shown sometimes on TVO here in Ontario.
These fellows pit their science knowledge against nature, and work out all sorts of interesting tools, cures, and machines from what they find around them.
I've actually only seen series I. They're up to 4 now. I hope the others get shown here in Canada sometime soon. You never know when you'll need to make a battery from seawater and a pencil.