use an episode from 아빠, 오디가? (Dad, where are you going?) or Gag Concert with English subtitles. Usually they're longer than 20 minutes or so. If not, 모한도전 also works. But try to have students pick out English words or sentences and write them down, then quiz them in the end of what English words or sentences did they wrote down. Works well in any grades. 3rd graders (low level) have them write down easy words. Advanced students who can write well have them write sentences.