We present experiences made with a course in applied computer science which was based on the concept of communities of practice. Within the scope of the course “Entrepreneurship and New Media” we offered a project lab which was accompanied by a set of lectures given by internal and extern lecturers. In the project groups, the students worked in close cooperation with start-up companies. The students were connected through a community system to each other and to their supervisors in academia and practice. As the communities of practice emerged we discuss the role they may play in teaching.