This paper focuses on engaging students in engineering education and provides a case study to exemplify one way of doing this proposing wikis as the main technology for delivering the content and collaborative problem solving as the main approach for working in class. In particular, we flipped part of an undergraduate course on Machine Design following specific design principles. The pre-course content was consisted of existing material, videos, texts and appropriate URLs. This was delivered through a wiki on the wikispaces platform. In class students worked individually and in groups on several types of problems, participating also in a peer review activity. We analysed interaction data recorded by the wiki as well as questionnaires exploring students' perspectives on the particular educational experience. Preliminary results of this pilot study provide evidence about the potential of the flipped classroom in activating students and in increasing interaction within the class.