This article introduces a new source - student graffiti - to university historians who wantto reconstruct the cultural history of student life. It shows how students at Utrecht Universityused graffiti to construct identities for themselves and their peers. These playfulgraffiti games have two important characteristics: (1) Graffiti do not simply describe theworld; rather they actively shape reality by constructing hierarchies among groups andborders between groups. (2) Graffiti are materialsemiotic writing practices, in whichmeaning is communicated through texts, images and symbols, as well as through writingmaterials, colours and the physical surface on which the texts or drawings are scribbled.University historians who want to use student graffiti should take these performative andmaterial aspects into account.