Here are some fun music related-links:
G'old [good old] Korean vinyl: Hongdae vinyl oldies bar Gopchang Jeonggol and concert promoter Super Color Super team up to rip tracks from the bar's extensive vinyl collection from the '70s to the '90s and provide mp3s. A mix tape (or mp3 collection) of several tracks they've released plus others can be found here.
Korean Indie: All you would ever want to know about Korean indie music including reviews and interviews by the people who brought you Korea Gig Guide and Indieful ROK. A brief history of the indie music scene in Korea is here.
If this is all too modern for you, how about a collection of Korean hits from the 1930s and early 1940s? (Hat tip to Jamie)
And looking at about the same era is Roald Maliangkay's article "Koreans Performing for Foreign Troops: The Occidentalism of the C.P.C. and K.P.K." (As the article notes, the "Chosen Music Club (C.M.C.) and the K.P.K., which derives its name from the initials of the family names of its three main members (Kim Haesong 金海松, Paek Ŭnsŏn 白恩善, Kim Chŏnghwan 金貞桓), were two variety show collectives whose activities from the late 1930s to the 1950s". The former performed for Japanese troops, the latter for US and UN troops.)
And for books ranging from recent to a hundred years old about East Asia, have a look here.