How to minimize the use of air conditioning

My wife recently pointed out to me that our new neighbors to the east of us have not used their air conditioner all summer.  This is despite many days in the 90's and some topping 100 degrees.  The previous neighbors seemed to have their air conditioner on most all of the summer.  What is the difference?  Our new neighbors hail from Peru, which is located fairly close to the equator.  They seem to be accustomed to living in hot temperatures without the luxury of air conditioning.  

For those of us unaccustomed to the severe heat, what can we do to minimize our use of air conditioners and hence reduce emitting CO2 into the atmosphere?  One of the things we can do is to open our windows when the weather cools later in the evening or early morning hours.  Sometimes we simply hang out in the basement where it is cooler or go to an air conditioned public facility if it is extremely hot.

It helps considerably that we live in a neighborhood with many large, mature trees. Did you know that... The net cooling effect of a young, healthy tree is equivalent to ten room-size air conditioners operating 20 hours a day.—U.S. Department of Agriculture.  You can read more about this in an article by the Arbor Day foundation, The Value of Trees to a Community. 

We also benefit from a home that has wide eves that provide shade to the walls and windows.

One the the best investments we made was to purchase and install ceiling fans in our bedroom, dining room, porch and study room.  These fans circulate the air, which makes it feel cooler to the skin.  They're also quite inexpensive and simple to install!

Lastly, we also make great use of a programmable thermostat that we adjust for different daytime and nighttime temperatures.  When we're out of town we also set it accordingly.

What are some of the things you do to minimize your use of the air conditioner?