Based on comments from a previous post I thought I'd explain what a swamp cooler is.
A swamp cooler (as named in the west - for sure in Las Vegas) is an A/C unit (I think it is also called an evaporative cooler) that uses evaporated water to cool down a residence. It is a large unit where the bottom serves as a water pan. Three of the sides (typically) absorb the water and draw it upward. The fourth side faces into the home (either attached directly via window or hole in the ceiling or tubing into the ceiling) and is the vent for the cool air. A pretty stong fan sucks air from outside into the unit through the sides that have absorbed the water and blows that cool, humid air directly into the home. They work pretty well to cool down an area quickly.
There are a few downsides. If the humidity of the house increases too much then the cooling decreases so you have to air out the house from time to time. Also, the pan holding the water empties quickly so they have tubing to bring water from the hose bib or other source to the unit. There is a float inside that regulates the water. These things (along with most of the rest of the unit) easily goes faulty and requires regular maintenance.
If a home doesn't have central air and there is no budget to have it installed then the swamp cooler is commonly used as a decent alternative.
When I was in college we lived with one and it worked well but it definitely wasn't central air.