This paper reports on a novel learning activity that aims at introducing machine learning contents in an Audio and Video Technologies study plan. The proposed methodology follows a Problem Based Learning (PBL) [Doud99] approach inspired in the actual problems solved by the researchers in the field. It was observed that this scientific community has defined very clear and evaluable strategies to test their approaches. There exist several evaluation campaigns whose completion require an understanding of the main concepts involved in machine learning [Smeaton09]. Moreover, their practical nature and transparent evaluation makes them very convenient to be used in a course to drive the learning experience of the students. The main contribution of this activity is a mapping of the classic stages in the definition and solving of a machine learning problem into a set of active learning activities aimed at solving a practical problem.