Few people have heard of it, yet many consider John Blankenbaker's KENBAK-1 to be the first commercial personal computer.
Free Solar Water Heater Book
By James Grahame
David Bainbridge (now an Associate Professor at Alliant International University) published The Integral Passive Solar Water Heater Book back in 1981. It has been out of print for many years, but is now available again on the 'Net as a downloadable acrobat file. I've only skimmed it, but there are a lot of clever ideas hidden on these 25 year-old pages.
"The water heaters covered in this book make a great DIY solar project. For a few hundred dollars and a weekend of labor, you can build one of these solar water heaters. It will pay back its initial cost in a year or two. One of these water heaters can save about 4000 KWH in a year -- about the same amount of energy that a 1KW PV costing around $10,000 would save!"
