This card game is great for all subject areas and all grade levels. I think it would be most effective in middle school - high school age students.
This game is completely editable so that you can add your own questions and answers. You can do less cards or you can add more. The basic idea of the game is for students to match questions to their answers. This game is played in the same fashion as the game "Old Maid."
Instead of an old maid I decided to have a theta symbol but you can easily change it to an old maid if you would like.
Depending on the intensity of your questions it can take 10 minutes or it can take an entire class period. I like to use simple math problems and I offer a prize to the winner in each group.