CAMPING -- Double the life of the ice in your cooler during long camping trips by wrapping it with your sleeping bag when not in use.
Better yet, I dedicate an old rectangular sleeping bag to the cooler and leave it on to insulate all day and night.
This past week, I had cold food on the fifth day of camping using that method with minimal ice. The sleeping bag's value was apparent every time I uwrapped the package for food and felt the outside of the cooler -- it was always cold to the touch.
On the fifth day as we ended a backpack fishing trek down the St. Joe River last year -- with temps soaring into the 90s, I surprised my sweat-soaked companion at the trailhead by pulling out a sleeping bag-wrapped cooler from the pickup and treating him to a very cold Corona.
He's a believer.