During oral exams at the German distance learning university, we noticed that students fear that they will be faced with questions that they have not anticipated. In our opinion, this is mainly because students have no chance to train and thereby gather positive experiences with exam situations as they are distributed all over Germany and thus it is difficult for them to meet each other. In this paper, we present a design space of 23 learning gadgets, i.e. tools that support collaborative learning, to allow collaborative exam preparation in peer-based distributed student groups. We discuss this design space according to eight dimensions of the concept of FLOW (Csikszentmihalyi, 1991) that constitutes enjoyable situations. Two of the learning gadgets were implemented and integrated in the CURE environment, a web-based collaborative learning platform that was developed to support different collaborative learning scenarios, e.g. collaborative exercises or virtual seminars. We discuss these learning gadgets in more detail and show how they promise an enjoyable collaborative exam preparation.