For the following suggestions, I always use lots of pictures on the big screen tv, or printed out and put up on the wall, visible to all. On Korean dramas there's loads of information and follow-up information just typing in the English language title into google. And even more pictures available if you can type the Korean names (of the actors and actresses) and titles (of movies and dramas) in hangul into google.
For boys: movies and Korean sports teams, especially soccer and baseball. You can use sports teams for colors, questions about mascots and locations (home city); what teams played last weekend or will play next weekend; who won or who's going to win.
For girls, K-Pop, movies and Korean dramas. Even some of the boys participate in the Korean drama discussions. All sorts of questions can come up if you use good visual aids: "What's their relationship? What kind of character is s/he? You can ask questions about the plot. What other movies or K-dramas has this actor or actress been in? etc.
I've gotten good discussion using the movie "Harmony"; and the Korean dramas "Secret Garden" and "Boys Over Flowers".
Also a random name picker available on barryfunenglish (requires paid membership; which I need to renew). It takes time to type in every students' Korean name, but you can save numerous name lists and the students will often pay attention at least long enough to see who's next.
It also allows you to make sure every student gets a turn to respond. Plus, you can let the current student walk up and touch the screen for picking the next student (more participation) This is pretty good for keeping focus and attention on the front of the room.
