During a large lecture class of 150+ students, we used a polling and live quiz tool called DirectPoll (http://directpoll.com/) to engage students in the lecture and test their knowledge on the topics covered.
This set of [slides][1] documents how students voted for answers to specific questions using the Direct Poll tool on their computer or mobile device. Correct answers were displayed once all votes came in.
[1]: https://osf.io/em2xt/