US burger chain Wendy's International is 'steaking' its latest advertising campaign on the rapidly growing incidence of late night munchies among its customers.  The Dublin, Ohio company controls the third largest hamburger chain in the US, and is confident that late night sales are the way to drive more growth within the market. Don Calhoon, Wendy's executive vice president of corporate marketing, commented that catering for consumers after 10pm "represents a sizable and viable piece of business."