Taekwondo — If you're interested in martial arts, you should learn Taekwondo. Taekwondo is originally from Korea, and you can study at any of the numerous schools all over the country. Taekwondo is a very courteous sport.
Chang or Pansori — If you like music, this will be good for you. It's a unique traditional Korean form of singing. If you want to learn about Pansori through film, "Seo Pyen Je" would be an excellent choice.
Korean — Seoul National University, Korea University, and Yonsei University (in Seoul) provide Korean language programs. You can meet people from all over the world while studying Korean.
Korean Traditional Dance — You can go to a dance studio and learn Korean traditional dance. You will wear "Han Bok" - Korean traditional clothes.
Baduk — Korean name for the ancient board game called Go in English. Many Koreans play the game, and among them are some of the world's finest players. There are even schools that specialize in Baduk.
Janggi — Also known as Korean chess, a board game similar to Chinese chess, with which it shares its origins, though the rules have diverged significantly from Chinese chess.