Socrative is an free online platform to quickly assess students. You can set up quizzes or exit tickets ahead of time or have students answer a "quick question" that you create on the fly.
Poll Everywhere allows you to create multiple choice, true false or open ended questions. It is a free program, but in order to see individual student answers, you will need to upgrade.
Kahoot! is a free fun engaging game-like quiz. Students are given points for answering correctly and quickly, and the teacher can see individual results.
