Split the class into groups of four and spread them around the room. Each team will need paper and pencils. At the front of the room, place copies of a document including all of the material that has been taught in some sort of graphical form--a spider diagram, for example. Then tell the students that one person from each group may come up to the front of the classroom and look at the document for thirty seconds. When those thirty seconds are up, they return to their group and write down what they remember in an attempt to re-create the original document in its entirety. The students rotate through the process until the group has pieced the original document back together as a team, from memory. These end products may be "graded" by other teams, and as a final exercise, each student can be required to return to his desk and re-create the document on his own.
Great article on Boys' Education