Postscript: another issue is time. Very often, you have n hours to cover m topics, and n always seems to be too small. This is unlikely to change. Active learning exercises tend to consume a great deal of time, to prepare, to run, to give feedback on. In general, you have to use the techniques sparingly, often reserving them for key issues or to help integrate knowledge about several topics. Lectures are often there to ensure at least a minimum amount of coverage of other topics, to offer an opportunity to ask questions and to clarify how a topic fits into the rest of the course. It seems unfair to examine and grade students on topics that were never taken up in class at all.