Marietta Square in the Dark: Goth Night 4 is scheduled for Saturday, October 24, beginning at 9 p.m. at The Brickyard, 129 Church Street. The event organizer describes a pre-Halloween night of dark music, costumes and dancing, with admission varying by ticket type.
The attraction is the atmosphere. You can make a night of dressing up, hearing music outside your usual rotation and seeing how the Square changes after dark. It is a more committed, adult-oriented outing than a daytime family festival, so decide whether that fits the mood before buying.
Check the event page for current ticket prices, door rules and the end time; the listing runs into the early hours of Sunday. There is no need to make it a marathon—arrive for the first hour if curiosity is the main reason to go.