Divide your class into groups of four or five students and give them each a list of 10 different geometric shapes, such acute triangles or rhombuses. Students will search the classroom for objects of each shape or which prominently feature the shapes. If you feel students are mature enough to act on their own and you have permission from other teachers, allow students to go to other rooms in the school to locate the items. The first team to assemble all 10 objects and have you verify them is the winner.
Split your class into two teams and have them stand at opposite sides of the room in a line. Each team will send a person to the board; you will show both players an example of a geometric shape. Both players will write as many facts about the shape as they can during a 30-second time period. Examples of facts would be: the number of sides the shape has, the equation for finding its area or the measurement of its internal angles. The team with the most accurate facts gets a point; the team with the most points when everyone has played wins.
Split students up into pairs. Give each pair a set of 10 slips of paper with names and illustrations of geometric shapes. One student will take a slip, while the other asks him yes-or-no questions about the shape until he has enough information to guess what the shape is. Questions could be "Does the shape have more than three sides?" or "Are the sides of the shape all the same length?" If the student can guess the shape within 10 questions, they get a point, and the player with the most points wins. This game should be used as a review tool after students have learned the features of different geometric shapes.
Make a sheet with 16 boxes. In eight, draw geometric shapes and in the other eight write these shapes names. In pairs, students will cut these boxes out, scramble them, and lay them face down in a four by four grid. Each turn, students will flip one box and then another in order to match the shapes and their names. If a student makes a match, he will remove the boxes from the grid. If not, he will turn them back over. Students will be able to get more matches by memorizing the locations of matching pieces. The student with the most matches when all of them are removed is the winner.