The Royale restaurant near Rogers Park commemorated its fifth weird year of business Monday the same way it celebrated its opening: with a vague attempt to attract customers by stringing brightly colored plastic flags from the mysterious eatery's storefront to a nearby utility pole. Residents have passed by the fluorescent-lit restaurant since 2006, bearing witness to three 'under new management' signs, the promise of live music on Tuesdays, and 24 mismatched and empty chairs. 'They're offering a 'buy one, get the second half-price' special,' local woman Michelle Durkin said. 'But it doesn't say what you have to buy one of. Actually, I've never really been too clear on what kind of food they serve there.' According to passersby, the ethnic-looking guy in an apron talking on a pay phone in the back looks like he works there. 