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The essence of ClassFlow is that teachers can not only nose around and pick the classroom activities, lesson plans and assessments that suit them, but they can also contribute to this online warehouse of curriculum. The marketplace is new but there’s already a slew of lessons, quizzes, presentations and ActivInspire flipcharts. Everything is rated by grade and carries a star rating. It’s free to join, but you’ll need to pay for those items you purchase.