Developed through Project Zero at the Harvard School of Education, these simple but powerful games are designed to develop students' critical-thinking skills and deepen their understanding of topics they are already studying. Corresponding to recognizable moments in instruction, the games, called critical squares, encourage students to go beyond rote learning to reflect on, analyze, and actively process the information and ideas they are studying. Four of the games have a roll-of-the-dice format; two are played like Tic Tac Toe. For each the authors provide start-up guidelines, sample student responses, and other pertinent information. Easy to learn, they readily fit into subject matter across the curriculum without major changes to content or structure. They can be used with almost any topic, in any subject area, and at any grade level from third grade on. Requiring almost no preparation time, these spirited games engage students while challenging them to think and learn. Grades 3-12.