Groups use rituals to create and preserve collective identities. Separation of sacred practices from customary activities has long been considered a key property of ritual. However, customary activities form the basis of some ritual celebrations. We explain how a different process of identity creation results: identity affirmation. We find that groups affirm their customary practices on ritual occasions when they intend to celebrate practices already associated with the sacred, and we explain the structure of such rituals using a case study of a university centennial celebration. We argue that attention to variation in ritual casts light on the values and collective identity of groups.