Negative questions can be confusing, even for native speakers, so how do you teach this difficult grammar point to students? Here are a few tips that I use in my classes that may also help you.
1. Tell your students that you think that they all like (for example) to watch horror movies. At this point, if they understand the statement, there are bound to be a few faces made, or a few NOs!! shouted out.
2. Tell them again, I think you all like to watch horror movies. Then say, 'Don't you like to watch horror movies?' The answer should be the same. Sometimes, you have to tell them that they like something a few times to get their excitement up, then switch to the question so they automatically answer.
3. Explain that if you use a negative question, it's because you think you already know the answer, but you're not absolutely positive. So, you want confirmation.
Making this a game is pretty easy, just use things that you are sure you know about them and say the opposite. This tactic works well for question tags as well.
I found a video and some exercises that will help along the way and will post them at the bottom. I'd love to hear from you about your experiences teaching this topic.
Online quiz: http://www.proprofs.com/quiz-school/story.php?title=Practice-Negative-Questions-1
Short explanation that you can copy and print out for students: http://www.englishpractice.com/improve/negative-questions/
A game you can make quickly yourself: http://www.waygook.org/index.php?topic=31771.0