Minimum Input Projects

Living amongst extreme poverty has gotten me thinking a lot about reducing the minimum cost of imputs, in both time and money, for starting projects. What are the cheapest tools you can make yourself? what is the cheapest house you can build? what is the cheapest way to get electricity? The cheapest flashlight? cheapest way to get all the nurtriants you need?

One Minimum Input Project I'm trying to get rolling now is for a photo project with kids at the school. I came across this design for a pinhole camera using 35 mm film and a match box, some electrical tape. If you use some expired film, than the whole project is pretty cheap.

Links:
Flickr photos with Matchbox Pinhole tags

Here's the website that explains the basic construction by the guy who designed it.