The teacher makes two sets of cards. One set contains questions related to the unit of study. The second set contains the answers to the questions. Distribute the answer cards to the students and either you or a student will read the question cards to the class. All students check their answer cards to see if they have the correct answer. A variation is to make cards into a chain activity: The student chosen to begin the chain will read the given card aloud and then wait for the next participant to read the only card that would correctly follow the progression. Play continues until all of the cards are read and the initial student is ready to read his card for the second time.
This is a good strategy for reviewing material. If you teach more than one section, you can turn the game into a timed competition between classes.