Heh, I was going to ask "what the heck is a cob house?", envisioning a house made of discarded corn cobs.
(Come on, I can't be the only one ... can I? OK, so I'm dim! )
But a side trip to Wikipedia tells me
Cob or cobb or clom (in Wales) is a building material consisting of clay, sand, straw, water, and earth, similar to adobe. Cob is fireproof, resistant to seismic activity, and inexpensive. It can be used to create artistic, sculptural forms and has been revived in recent years by the natural building and sustainability movements.
Neat! 
DH and I took a drive up around that area yesterday. Even in the rain, its lovely.