‘Public engagement with science’ is an increasingly important but contested practice. In this study of London's Dana Centre I look at dialogue events carried out there as a case study of public engagement, performing a detailed analysis in order to examine their nature and practice. The analysis suggests that event framings (as found in the discourse of events) are multiple, varying from lecture to open debate. Furthermore the genre of events is flexible, with participant involvement organised through the use of genres derived from education, talkshows and news interviewing as well as more traditional genres such as lectures. While it seems there is flexibility in the practice of these informal dialogue events, they are, however, not open to reinvention by all participants equally. The fluidity of practice observed may be due to the newness of these kinds of processes in most people's experiences. We are therefore observing, on the ground, the traces of contrasting discourses of the right relationship between science and society.