The Teenage Liberation Handbook
This is not a curriculum, per se, but it is an excellent resource for anyone looking to go with a more relaxed approach to any or all subjects. The book is written for teenagers, but parents can benefit greatly from reading it, too. It's a wonderful book, too, in that you don't have to read the whole thing to get the point. You can read whichever part of it that meets your needs.

There's even a chapter on the legalities of homeschooling around the world and how best to deal with them.