This paper presents the design, implementation, use and evaluation of a tangible data souvenir for an interactive museum exhibition. We define a data souvenir as the materialisation of the personal visiting experience: a data souvenir is dynamically created on the basis of data recorded throughout the visit and therefore captures and represents the experience as lived. The souvenir provides visitors with a memento of their visit and acts as a gateway to further online content. A step further is to enable visitors to contribute, in other words the data souvenir can become a means to collect visitor-generated content. We discuss the rationale behind the use of a data souvenir, the design process and resulting artefacts, and the implementation of both the data souvenir and online content system. Finally, we examine the installation of the data souvenirs as part of a long-lasting exhibition: the use of this souvenir by visitors has been logged over 7 months and issues around the gathering of user-generated content in such a way are discussed.