I thought it is time to share some experience with plenary discussions in a class of 70 or thereabouts.
Over the last year and a half, we have developed the activity module JazzQuiz. It is based on ActiveQuiz, but we have removed auto-grading, simplified the interface here and there, and most importantly, added features to improvise questions, where the question is given on the blackboard and moodle allows the students to answer from whatever device they have at hand.
Quiz as contest or game is readily handled by existing modules. The focus of JazzQuiz is realtime interaction with the students.
1. Improvised questions means that I can ask follow-up questions depending on how the students have responded to previous questions.
2. As a short answer, I can ask the students for questions, providing an opening for students too timid to raise their hand and ask in person.
3. All student answers are displayed, and can be viewed by the class. Misconceptions can be discussed straight away.
4. Evaluation questions can be asked at any time. Do we proceed too quickly or too slowly? In many cases, action can be taken straight away, and the students can see how their feedback is applied.
5. Problem-solving can be undertaken by step-by-step quiz questions. First brainstorming: what methods can we use? Then questions about individual steps of the solution. Where multiple approaches exist, the students may choose. (I teach mathematics btw)
6. Short answer and similar question types can be followed up with a multiple choice voting over the answers which came on the first attempt.
7. et cetera ... I don't assume that I have seen all the possibilities
My experience, from using JazzQuiz for a full semester last Autumn, is that it creates an eatmosphere of discussion, and makes it easier for the students to talk to eachother and to the teacher, and discuss both the subject and the learning.