Primitive Ways makes use of the internet to teach us the lost knowledge of our Stone Age ancestors: making fire, tools, weapons, cooking utensils, musical instruments, shelters, and much more. Not everything is that useful in the 21st century, but the site contains a wealth of information and many of the diy-projects sure look like fun. Moreover, they also combine traditional skills with modern materials, like in this four-hour kayak. Some articles are extremely short, but very useful - see the Inuit Thimble, for example.
Primitive Ways is also available as a book or a dvd, but all information is freely accessible on the website. Articles also appeared in the "Bulletin of Primitive Technology", a print magazine from the Society of Primitive Technology.
Another good resource is "Primitive Technology: A Book of Earth Skills", available on Amazon. Update: "The origins of invention: a study of industry among primitive peoples".