A seemingly small fire broke out in the Sounds building on St. Mark’s Place this morning around midnight. At 12:30, firefighters pushed through the throngs in Grassroots Tavern; broken glass fell into the bar’s backyard as firefighters shattered windows above. The fire was on the top floor, the bar’s bouncer said. Third floor windows were open, though no flames were visible, and an FDNY ladder extended to a single attic-like window sticking up off the roof. A strong burning smell drove many tavern patrons out onto the street, where several fire trucks had closed traffic, though the basement bar seemed to go unevacuated. Dozens of onlookers gawked as firefighters wrapped up unused hoses, and residents of the neighboring building stuck their heads out to watch. The building did not appear to suffer substantial damage.