Parabolic solar cookers could be a life saver for millions of people who cook over smokey wood fires every day. This has already ruined countries like Haiti, where much of trees and forest are gone and is causing the rapid ruin of many countries in Africa too. But keeping the parabolic cooker pointed at the cook pot and at the sun is a fine art where you have to move the entire contraption every 15 minutes or so. No fun in 90 farenheit!
This shows a model of how it can work on equatorial mount. (similar to telescope mounts).
This would make tracking, either manual or by motor a breeze. What are we waiting for?