We have these things in the desert Southwest known as "swamp coolers." Basically, they cool homes through evaporation of water and circulating air with a fan. That's pretty much the same theory behind designer Thibault Faverie's Cold Pot, a concept for cooling.
The terracotta container looks like it should have a spider plant growing out the top, but what it actually contains is an internal aluminum radiator system and a blower to circulate air.
Faverie chose a terracotta shell for its ability to absorb and release water, so it acts like a heat exchange. The Cold Pot is designed to function using about half a gallon of water.
The water gets sucked into the inside of the pot, where it migrates to the outside surface and slowly evaporates on contact with the air. This cools down the aluminum pipe inside and cool air from inside gets blown out into the room.
The idea behind the Cold Pot is certainly intriguing, but I would have to try it out to see if it really makes a difference. There may be limitations as far as the size of the room it can cool, but future versions or larger versions of the device may take care of that issue.
A small, portable cooling system with low energy and water use would be a very popular product in dry areas of the country. I'm looking at you, New Mexico.