7Play is not just for kids and the young at heart. Boring grown-ups play too, but we only unleash our imagination with close friends and family. Still, our propensity to play is nothing to be ashamed of, according to Marc Malmdorf Andersen, play aficionado at Aarhus University. In fact, play is a sort of scientific process, and by testing one hair-brained idea after another we not only become better, more creative adults. We can also make love grow, and maybe even save the world. This might not be as crazy as it sounds, and it's guaranteed to be a barrel of fun.