You put kids in groups and within five minutes someone is bossing, someone is checked out, and someone is in tears. Cooperation isn’t natural—it’s a skill we have to teach explicitly. Best cooperative structures for classrooms: 1.  Silent Line-Up Kids must line up by birthday/shoe size/height without talking. Forces non-verbal negotiation and laughter. 2.  One Paper, One Pencil Challenge Give a group one sheet of paper and one pencil to complete a task (draw a house, list 20