Labor Day weekend got off to an exciting start Friday morning for the people who work at the City Hall Annex on Bay Street. A fire alarm went off in the building and the staff at the State Attorney’s Office climbed down the stairs and strolled over to Jesse DuPont Park at the corner of Forsyth and Newnan streets. One person described the precautionary evacuation as a “field trip” and another asked his colleagues to join him in a little Tai Chi in the park. After a few minutes, the “all clear” sounded and everyone headed back to their desks to finish the day before beginning the long weekend.