CereBellum: Didn't know they had cooling gel mats for dogs...there's an idea....
Fireball: I used to soak handtowels in water and then put them in the freezer, when they were frozen I'd wipe myself down with them. And drank a lot of ice water too.
Sleeping: A kiddie pool looks good when I'm overheated walking across a parking lot to the store...
Too bad homes are no longer built to pull a good draft through them. A dog-trot type home would really be helpful, could cook in one side of the house, sit in the middle to cool down and go to sleep in the other half of the house.