I never been to this place at night, but during the day, you can spend time here after strolling around Hongdae area. Its pretty quite during the day, usually just some students or people exercising. And do not forget to buy 1000 Won WAFFLE ICE CREAM before coming to this place! there are small food shops outside this park, they are cheap, and you can enjoy them in this beautiful park! good idea, isn't it?