I competed in a strong man competition this past summer, flipping a 550lb tire, farmers walk with two 180lb cylinders, pushing a truck 120' for time, etc. I finished in the middle of the pack. I thought that the powerlifter who was competing would take it easily, but in the end, a big farmer that did not lift weights won the whole thing. The farmer was naturally big, 6'3", 260 lbs. But didn't look that strong. He does work a dairy farm daily though.
The functional strength of the strongman was a lot different from the weightroom. It was a good experience but I won't do it again. I hurt for a week afterwards.
http://www.youtube.com/watch?v=xsvrgA-ZuWY