Tasks can be: games, competitive games, problem-solving activities, role plays, creative tasks e.g. building, drawing, writing, researching. Make task instructions clear: written, spoken, demonstrated. Make aim of task clear: completion? creativity / originality? competition with other groups? (based on speed? efficacy? quantity? originality? etc.). Set a time-frame (tasks can last part of a lesson, a whole lesson, continue over a term etc).