Make up 60 or so questions based on material already covered. The questions can be comprehension questions, fill-in-the-blank, translation, etc. Divide the class into two teams. Give half of the questions to one team and half to the other. Get the students to work in smaller teams within the teams to find out the answers to the questions. Then, stage a contest between the two teams. One team asks someone on the other team a question. If it is right, the student gets a point for the team. If it is wrong, the asking team gets a point. Students can also add their own questions to the ones that you give them. Also, you can add in an element of the unknown by adding in questions like Let Mr./Ms. ~ ask the other team a question. Then, you get a chance to ask the question.