Seoul Calligraphy Art Museum:
Daily: 11 a.m. - 8 p.m. ( - 7 p.m. November - February)
Closed every last Mon of the month.
World Music Fountain:
Operates between March and November, closed on rainy days.
Mon: 6:30 p.m. - 8 p.m., 9:30 p.m. - 10:30 p.m.
Tue - Fri: noon - 1 p.m., 6:30 p.m. - 8 p.m., 9:30 p.m. - 10:30 p.m.
Sat - Sun, public holidays: noon - 1 p.m., 3:30 p.m. - 4:30 p.m., 6:30 - 8 p.m., 9:30 - 10:30 p.m.
You can find more detailed schedule of the fountain, events and performances on the official website.
Box office (Service Plaza in the Vitamin Station): daily 9 a.m. - 8:30 p.m.
The admission fees vary for every exhibition and performance, some are free. See the detailed overview on the website.