Duval Guillaume are showing off their bottle-opening skills and their trademarked modesty with their best ad in the world for Carlsberg, who knew that a few simple folds could open a beer bottle? I knew, I've seen people open beer-bottles with lighters, pens, edges of the table, rings and all sorts, including folded paper which is almost as impressive as when a drunk french man uncorks a wine-bottle with his shoe. I can't do any of those clever opening tricks, but I can open beer bottles with my teeth. Calcium. It's key.