Start by a 3-hint quiz about their teachers (three is okay). You may ask a favor from two other teachers (JTE and 1 more) to give you facts about them. (e.g. It's bad for me to eat chocolates./It's difficult for me to eat umeboshi./It's important for me to visit the doctor every weekend.)Let students guess all of the 3 quizzes before revealing the answer.
After the teachers' quiz, let students make their own by giving not-so-obvious hints. I've attached a ready-to-print sheets, but you can customize your own.
When everyone is finished, collect the paper and randomly distribute it making sure that they won't get their own. To avoid this, I collected the first half while the JTE collected the other half of the class' paper, then we just exchanged them and distributed it flipped over individually. At this moment when students finally understood what to do, they would instantly show interest on what they're going to do next.
Let students stand up and do the activity. We preferred students do their free conversation (which means no script) in quizzing their classmates. We like seeing students think of their own sentences on how they would start and do the quiz. (They tend to use sentences we've used before and which they are familiar with like "Are you ready"? Who's this?" "I think it's~" "Is it~" "That's right" "No, it's not (Yamato)"
Instruct the students to use the third person pronoun when quizzing other students. That will serve as a hint. (e.g. It is necessary for him/her to~)
Encourage students to write the names of those who guessed it correctly at the back of the paper.
After several minutes, ask each of them to return the paper to the owner. Most students will be surprised of the results, especially when they find out there are some who could still guess that it's them even though it's difficult! Others might find out no one has guessed who they are, in which some might feel bad about it, so we just told them that they made a great quiz that no one was able to guess!