"Play engaging quiz-based games (kahoots) at school, at home and at work, create your own kahoots and learn something new! Kahoot! brings the magic of learning for students, teachers, office superheroes, trivia fans and lifelong learners."
"Plickers lets you poll your class for free, without the need for student devices. Just give each student a card (a "paper clicker"), and use your iPhone/iPad to scan them to do instant checks-for-understanding, exit tickets, and impromptu polls. Best of all, your data is automatically saved."
"Quizlet is the easiest way to study, practice and master what you’re learning. Create your own flashcards or choose from millions created by other students. More than 50 million students study for free with the Quizlet app each month!"