Based on your previous info, I just found out there's a science museum 國立果川科學館 at Seoul Grand Park where there's a Seoul zoo, and Seouland. Wow, there're plenty of things to do at that metro station. Gotta to plan for a full day there!
I have bought Nanta show tickets for Sat 2:00pm, hence thinking to take photos between 10:30am-2pm.
I know the page is in Korean when I want to become Kidzania member, hence I emailed them, but they NEVER reply! Still worried whether there will be a lot of people on 30 Dec 2013.
I am taking 8:00pm flight back to HK. In that case, what time should I go back to hotel to pick up my luggage and go to the airport? I will stay at Myeong Dong.