How to light a room without electricity with water filled plastic bottles. It couldn't be easier. This is a film from the Phillipines where corrugated iron roofs make homes dark 24 hours of the day. This idea could be applied to cob and adobe houses as well and of course garden sheds!
The idea was pioneered by Brazilian Engineer Alfredo Mozer in 2002 - see http://www.youtube.com/watch?v=_zMAWztZ6TI&feature=related
For more practical articles, features and stories of hope please subscribe to Permaculture magazine.