The paper discusses the various situational features and linguistic devices reflected in the three most interesting and the three least interesting postgraduate second language acquisition lectures taught by three lecturers. Students attending the classes were invited to record their interest level at regular intervals throughout the session. For each lecturer observed, both the most and the least interesting lecture reported by students were chosen for detailed analysis in terms of four situational factors: lecture content, lecturing style, tasks and the personal behaviour of the lecturer as demonstrated in the lecture. Several characteristics unique to the three most interesting lectures as compared to the least interesting are discussed: the contextualisation, concretisation and personalisation of the topic through the use of vivid, concrete examples; the participatory style of the lecture where students are involved in the kind of thinking that characterises the discipline or the particular discourse community; the use of open, but goal-directed tasks which encourage exploration of ideas and disciplinary thinking, and the lecturer's demonstration of enthusiasm and positive stance towards the lecture topic. The paper also discusses various linguistic devices, which help promote the interestingness of the lecture content and its closeness to students' reality. (Contains 1 table and 5 notes.)