There is a lot of information on the internet about primitive shelters. Some shelters require nothing but a knife and a little hard work. Other shelters require a knife, some cordage (twine or string) and a little ingenuity. Lastly, some of these primitive shelters aren't really primitive because you need a tarp to build the shelter.
Well, during my research (really just surfing the 'net), I came across some web pages that have information about different shelters that don't fit into a particular category of primitive shelter. So, here are those links.
Pine Home - Primitive and Low Tech Shelters
Rouge Turtle - Cold Weather Shelters
Practical Survivor - Wilderness Survival Shelter
Coalition Against Civilization: Forum - Temporary Primitive Shelter
The Central American Sea Kayak Expedition - Ignacio's Cohune Palm Shelter: The Kekchi Indian Technique of Blue Creek (Belize)
UW at La Crosse: Department of Sociology and Archaeology, Elizabeth Schultz - Sewn Cattail Mats
Note: Make sure you check out her Cordage page. The link's below.
UW at La Crosse: Department of Sociology and Archaeology, Elizabeth Schultz - Construction: Cordage
NativeTech: Native American Technology and Art - Photographic Tour of Contemporary Wigwams