This demonstration provides a "hands on" experience to the "internals" of Pergamos, the University of Athens DL System. Pergamos provides uniform high level DL services, such as collection management, web based cataloguing, browsing, batch ingestion and automatic content conversions that adapt to the underlying digital object type-specific specialities through the use of Digital Object Prototypes (DOPs). The demonstration points out the ability of DOPs to effectively model the heterogeneous and complex material of Pergamos. Special focus is given on the inexpensiveness of adding new collections and digital object types, highlighting how DOPs eliminate the need for custom implementation.