I have one project for each course. I work from my course syllabus for overall structure, and generally prep lectures and problem sets the night before class, because I like to be fresh with the material. These are on my calendar, but also repeating next actions. I will also have next actions for things like emailing a document to the entire class, or grading an exam. Occasionally I will have a next action to plan a sequence of lectures on, say, solar energy.