Located a short walk from Seodamun Station's number 5 exit, the Seoul Agricultural Museum is a pleasant way to pass half an hour or so if you're in the vicinity. The three-story building contains more than 2400 items relating to Korea's fast disappearing agrarian culture.
A small garden stands outside the building, with an operational rice paddy and a small water mill serving as highlights. English language leaflets, dispensed at the reception desk, detail the main exhibits and contain a floor plan.
Highlights include a collection of large Baekje era jars, which were once used for storing grain, as well as a number of village flags, or Nong-gi, which were formerly flown during ceremonies and festivals. There are also several interesting displays of traditional farming implemements and household items. To the left of the Agricultural Life Hall on the second floor, a small room details the many different varieties of Gimchi, with models accompanied by good English text.
Admission to the museum, which opens from 9.30am-5pm every day except Monday, is free. I wouldn't recommend a special trip here, but if you're in the area and have some time to spare, it gives an interesting insight into an aspect of Korean life that still resonates with even the most urbanised of Seoulites.