EDIT: Fixed some slides and rearranged some others.
The way I do it in class is I have them made their usual lunchtime groups and decide with rock paper scissors which person and which group starts.
Rather than having each student answer on their own, I let them discuss amongst themselves, the point is to have fun after all and learn at the same time, but only the student whose turn it is answers, then after every team plays and it's back to the first team, it's the next student and so on.
If a student can't answer a non-multiple choice question, whoever answers from a different team gets the point.
If it's a multiple choice, I made it so wrong answers disappears and the next group chooses. If it gets down to two answers and the group gets wrong, then nobody gets the point.
At any time if a student can't answer in English I grant them half points for answering in Japanese (again, this is for them to have fun, not stress) and whoever can answer in Englisn in another group gets the remaining points.
Choose however many seconds to answer you want.
The last 10 minutes I do 2x points.
These rules are still work in progress, tell me what you think.
Feel free to change questions as you see fit.
thanks so much