Window air-conditioners is what we use. We have one in the living room, one in the kitchen, and a small one in the back bedrooom.

One option that I have in my MH to use when relying on fans only is to turn OFF the thermostat and then use the "Fan Only" option on the furnace, in essence using that option will pull UP the cooler air from under your home and blow it through your normal "heating" vents. It's certainly not A/C but the air under the home is always 10-15 degrees cooler than the outside and/or inside air so it does make a difference. Up here in Maine I'm starting to miss those hotter days of summer already.