Go out and find an "Oust Fan". I picked a couple up at my local grocery store. (here's an example) ---> http://www.amazon.com/Oust-Portable-.../dp/B000XR4F24

I replace the D battery in it every 3-6 months, and it works great circulating the air. No muss - no fuss. And you can put it anywhere you want within the cooler. .

..just don't install the oust "scent" package, or you'll end up with Acid cigars.