I thought this article was very interesting and I have never heard of it before. It is called a Zeer Pot. It is used a lot in Africa to store perishables. Meat can last up to two weeks in it.
It works much like an evaporative cooler. I am going to try this as soon as I can find free pots on Craigs list. We take for granted our appliances but we may be in a situation one day when the frig dies and we just don't have the money to buy a new one.