http://mb-soft.com/solar/saving.html
Imagine if you happened to live directly over Mammoth Cave in Kentucky. Down below you, on a 95ºF hot summer day, there was all kinds of 56ºF air down in the cave! So imagine that you bored two large holes down from your house into the ceiling of the cave. You would then be able to use a standard furnace blower to draw air up one, to push it into the house through your existing heating/air conditioning ducts and registers. The second duct would be to allow your hot house air to go back down into the cave to replace the cool air you removed. Presto! You have awesome air conditioning!
