According to a CBS News article (via Leiter), a couple of logic profs at Smith College in Northampton, MA enlisted their students to play a hoax on the rest of the school.  They instructed the students to spread the idea that the school was planning to adopt an all locavore and vegan menu in the cafeteria.  Then at a certain point they, with the help of the college President, double-tricked the class into thinking that it was actually true.  Here's the question (the question I actually made my Phil 210 students write about): what kind of lesson can one learn from this kind of hoaxing? 

It seems to me that this one has such an air of plausibility (except maybe the vegan part) and authority (the President played along with part of it) that one learns a grim lesson: trust no one; they might be trolling you.