Lots of Travel info on Korea, things like accomodation, and sights. Travel Information
The next 2 links are from Purdue and give good information about Korean Holidays, Festivals and cultural things.
Korean Special events
Korean Culture
This is a site about Korean traditional Masks and Performances.
This is a link to the Seoul Computer Club
If you're interested in Walking event this Miningco site will be interesting. It has lots of other information about tons of stuff. Have a look