A recent TEDx Talk by Will Stephen is the new "Dr. Fox Lecture." In the 1970s researchers designed an experiment to see how a group would rate a short lecture by an actor, trained only the day before, who charismatically presented bunk (Naftulin, Ware, and Donnelly, 1973). The audience was a classroom of experts, psychiatrists and psychologists, but the topic was irrelevant to their expertise -- it was also nonsense. The Weird Experiments site now has video of the Fox lecture and concludes that the "The experts didn't notice a thing." (Kulik 2001, pp. 17-18 also has a nice description in the context of student ratings of teachers.)
Both of these videos show that a well presented talk about nothing can seem compelling. Rather than despairing, imagine what we can do if we use these techniques to actually impart content!