Purpose Games is a free service that allows users to create custom games, share games, and play games. There are two styles of games that you can create and play on Purpose Games. The simpler of the two styles is a fairly basic multiple choice game. The other style uses images and maps on which players have to name the places represented by placemarks on the image or map. For an example, try this game about the skeletal system.
Purpose Games gives game creators the option to make their games public or private. If you select the private option, only the people to whom you send invitations will be able to play your game.
Applications for Education
Rather than relying on games made by someone else who has never taught your curriculum, try using Purpose Games to create an educational game to match your curriculum. You could also have your students create games for their classmates to play as a review activity.