Oct 3 · times vary by programmeDongdaemun Festival, one day along Janghan-ro
The Dongdaemun Festival takes over Janghan-ro for a day, run by the Dongdaemun Cultural Foundation. It is open to everyone and free to attend, a straightforward local festival day rather than a tourist production, which can make it a nice way to see the neighbourhood on its own terms.
The festival runs across the day with a mix of programmes along the street; exact schedules differ by programme, so it is worth checking the official site before you go so you can catch the parts that interest you.
It takes place on October 3, along Janghan-ro in Dongdaemun-gu. Admission is free. Programme times vary, so check the link for the day's schedule.