Underground Printing employee Shelby Melton organizes T-shirts while working the counter on Sept. 4. The Ann Arbor-based Michigan retailer is preparing for its busiest weekend of the year with the second-ever night football game.Melanie Maxwell | AnnArbor.comFootball Saturdays are typically the biggest sales days of the year for Ann Arbor-based retailer Underground Printing, but Michigan Stadium’s second-ever night game should deliver an unprecedented business boost.Continue reading Michigan Stadium's second-ever night game means big boost for Ann Arbor businesses...