The interactive lectures are currently based on the article of Deslauriers et al. (2011) on Improved learning in a Large-Enrollment Physics Class that appeared in Science. This comes down to the use of a number of different techniques of which the most important are pre-reading assignments, pre-class quizzes, the use of clicker questions and in-class group tasks, allowing for just in time teaching (which I think is a bit of an excessive word for what it is, but ok).
Students can receive bonuses by completing pre-class quizzes and by answering in-class questions.
Students (or others) who have suggestions or remarks concerning the way these lectures are organised can always leave a comment here!