The Hexayurt is a new kind of sheltering solution. To make the simplest hexayurt, make a wall by putting six sheets of plywood on their sides in a hexagon. Cut six more sheets in half diagonally, and screw them together into a shallow cone. Lift the roof on to the wall with a large group of people, then fasten it down with more screws. Seal and paint it for durability. Your basic hexayurt is complete. This shelter will last for years in most climates and costs less than $100. This basic design can be improved with proper windows, doors, room partitions, stove fittings and other architectural features. More durable materials could give it a very long life.

http://hexayurt.com/

I found a little more information on the Science for Humanity site.

And the schematics on Appropedia.