Here is a website devoted to something that looks like an interesting lecturing strategy. The basic idea is that every fifteen minutes or so, the lecture is interrupted and students are asked a quiz question. Then, those who got the aswers right are supposed to convince their neighbors who did not get the right answer about it. The method (i) provides the lecturer with insight into how many of the students understand the material, and (ii) makes students think harder. Here is a paper where the effectiveness of this method is studied. I might try it out some time.