The large delta in temperature makes our area perfect for a whole house fan. These are powerful fans that pull air in at night cooling off the house and the attic. You then turn them off on the morning and close up the house to contain the cool evening air.
Our house is over 2600 square feet so we needed a large fan. We decided to go with a 6400 Cubic Feet Per Minute (CFM) Quiet Cool Fan from Whole House Fans. I roughly estimate the volume of our house to be around 22,000 cubic feet which means the entire house volume in about 4 minutes. Of course, it takes quite a bit longer to cool off the house. You have to suck all the heat out of the furniture walls, and electronics in the house.
The fan came in a large box and was VERY heavy. We had to pull the pieces into the attic one at a time.
Once the hole was done, we were able to install the plenum between the joists.
The fans hang from the rafters and connect with large hoses. Since the fans are isolated from the ceiling joists, the fan runs quietly. This is important since we like to run it through the night.
There are other kinds of fans that are cheaper. Though they are also quite loud and didn't have the CFM needed for our house. The Quiet Cool fan has been a great way to cool down the house for the hot summer days. It was an expensive fan, so not so sure it will pay for itself. Though, I'd rather have fresh cool evening air than stuffy A/C.