If you are looking for a fun and effective way to assess your students knowledge at the end of a unit or introduce a bit of competition into your classroom then you might want to check out Kahoot.

Online at https://getkahoot.com/ to sign up or https://kahoot.it/#/ to play.
You can add multiple players to a quiz to have them compete for the most points. Points are warded for correct answers and for speed of response.

Create and play quizzes, discussions or even surveys using any device with a web browser… including a laptop, iPad, iPhone, iPod, Android, Chromebook, Windows Phone or PC and more.

Students sign in to the quiz on their own device using a simple game pin.

In this video https://www.youtube.com/watch?v=fnh0Qkfr044 a teacher share how they have used Kahoot to increase vocabulary knowledge by having students create their own quiz around a vocabulary list.