So how do I fill the time that I would normally lecture?
I usually begin with an informal review, taking questions from students, and adding my own, based on previous experience and feedback from the online quiz. In some cases I add new material that is not in the videos, usually later in the class because I want students to have an opportunity to draw their own conclusions first. This is also an incentive to come to class.
In many class videos, I pose questions that I expect students to complete and discuss in class. These serve as a starting point for further discussion, and serve as a check on the level of participation during video viewing.
The rest of the class is spent working on an activity (or combination) of activities, usually in teams that are set up for the duration of the semester. These include discussions, peer teaching, problem sets and building models. In each case, I circulate around the class offering feedback and guidance in “real-time”. Sometimes I use the time for other activities like practice exams or a discussion on learning and studying.