We present Toccata, a system that facilitates the management of rich multi-device pedagogical activities. Through interviews with high school teachers, we identified a set of barriers to conducting digital activities in schools: setup time, network problems, difficulties in following and changing plans as activities unfold. We designed and developed Toccata to support the planning of pedagogical activities (scripting), seamless sharing of content and collaboration across people and devices, live management of activities in the classroom, roaming for situations outside classrooms, resumption across sessions, and resilience to unstable network conditions. We deployed Toccata in three classes, over seven teaching sessions, involving a total of 69 students. Together, these deployments show that Toccata is a generic solution for managing multi-device activities in schools. We reflect on how Activity Based Computing principles support Orchestration in Toccata, and discuss the design opportunities it creates such as better awareness of learners' activity, micro-orchestration techniques for enabling teachers to better control devices in classrooms, or supporting reflective practices of teachers.