Way back when ... After a good summer weekend hike, after we tied up the pack dinosaurs, my friend asked I could do with a beer. I figured he had socked a few away and it would be, at best, tepid.

Instead he pulled out a Styrofoam cooler holding a six-pack, a CO2 fire extinguished and a proceeded to discharge the cylinder into the cooler. In about a minute we had frosty cold beer. A grand way to end a long summer hike.

Now this isn't a very efficient or cost effective system for most people. He could do it because, as part of his job, he could refill the fire extinguisher for free.