It seemed like a good idea at the time

We often learn of successful pedagogical experiments, but we seldom hear of the the ones that failed. From an epistemological point of view, learning from failures can be at least as effecitive as learning from good examples. This special session has a structure similar to that of Parlante's Nifty Assignments, i.e. we solicited submissions from the SIGCSE membership, selected the best from among these, and have presentations at the session by the selected authors. Our contributions describe pedagogical approaches that seemed to be good ideas but turned out as failures. Contributors will describe their pedagogical experiment, the rationale for the experiment, evidence of failure, and lessons learned.