When teachers plan pedagogical activities, they define the pedagogical strategies, resources, and tools they will use. But, as they run these activities in class, they have to adjust their plans, according to available resources, and to live breakdowns. Teachers have very little time to adjust their plans in class, and existing tools offer very little support for live changes. We conducted contextual interviews with eight middle and high school teachers to better understand their practices in planning and enacting pedagogical activities. We identify a set of breakdowns in conducting their activities, and the strategies teachers develop to cope with them. Teachers use digital tools to keep a trace of their plans and to improve their enactment strategies. They design plans students can enact directly, or define the content, the structure, or both, with students in class. Most enactment issues are software and hardware breakdowns. Based on our findings, we propose implications for the design of novel tools to support teachers in enacting their plans in class. These tools should capture traces of the activity as it happens. They should support externalizing plans, and sharing them with students. Ultimately, plan- ning and enactment tools should support richer cross-device interactions.