EVANSTON — Last Sunday A&O hosted a Dance Marathon benefit concert featuring the San Francisco band Geographer. The concert was held out on the Norris East Lawn and was well attended, though the crowd was a departure from the indie band’s usual fan base. Geographer’s manager described the band’s average fan as “a young blond girl with a California tan, usually wearing some combination of swimwear and clothes that I can only assume she stole out of her grandmother’s closet.”