In deciding whether to choose a real event from which to develop children's mathematical understanding, it is crucial to have a clear appreciation of what mathematics pupils need to learn. In this article, the author looks at the issue of "context"--the positives, and negatives for the learner. He describes a project in which the context became the learning objective itself, however, as planning for the project developed and crystallised, the context was seen as the vehicle for the key learning objectives.