How does a free trip to Korea -- offering roundtrip airfare and a three-nights' hotel stay in Seoul -- sound? As a way of promoting knowledge of Korean culture and tourist attractions, the Korean National Tourism Organization has put together an online quiz, with the free trip as lure. Complete the quiz at the KNTO Web site and your entry will be dropped into a computerized lottery system. If you win, you'll be able to fly to Seoul and stay at the Hotel Shilla for free. And you may just learn something new about Korea in the bargain. Entries must be received by Dec. 31, 1997.