A Coca-Cola vending machine was placed at the Royal Institute of Technology in Stockholm during students’ finals, but instead of a logo on the front, the iconic red machine read “Sing for me.” Students who sang a Christmas carol were rewarded with a free Coke. A touchscreen allowed students to choose from a short list of Christmas carols, and two microphones let friends get in on the action. As soon as they sang the tune, a free Coke was dispensed. Needless to say, the machine proved to be quite popular. Some may recall that Coca-Cola managed to grab attention last spring with its “Hug Me” vending machine installed at the National University of Singapore. Instead of money, this machine responded only to the currency of hugs; students squeezed the sides of the soda dispenser to get a free Coke. Both are part of Coca-Cola’s global “Happiness” marketing campaign.