Traditional project management approaches encompass the idea of uncertainty, but there is no established managerial practice able to deal concretely with the Unexpected, that is some practice that helps managers to deal with events that have already taken place but that were not anticipated in their planning, so that - in order to remaining "on track" and to succeed, radical changes are required. In this work I examine how project teams and managers react to Unexpected and how they are able to cope with high project Uncertainty. In order to draw some practical conclusions, the work will analyze both the Organizational responses and the "Human"/Behavioral responses. I will try to shed some light on the different approaches to Unexpected Events Management through a literature Review of Project Management Methodologies and Techniques, followed by an analysis of new approaches to the Management of Uncertainty, and a detailed description of the LHC case study, a large-scale, international, and high-tech project: how the Team has approached and dealt with the Unexpected in that particular case, and which of the previously seen methodologies are used in practice by project managers.