If you haven’t heard about Kahoot yet, then make sure you have a look at this link. Sign up for a free account and you will immediately be able to create fun, interactive, online quizzes for formative assessment in the classroom; it’s a great way of breaking up lectures and gauging student learning.
I’ve used this in a class with about 150 students and they were completely engaged. They use their mobile devices or laptops to answer quick quiz questions in a fun and engaging manner. Answers are recorded by simply clicking on the colour or shape (they’ve even catered for colour blind students) associated with the correct response. At the end, you can show the class the responses and discuss why incorrect answers were chosen. A great learning tool, accessed easily via kahoot.it and a game number provided by Kahoot once you have designed the question. You won’t look back!