Although a lot of things have changed in the field of advertising over the past few years one thing has stayed almost constant: the billboard. Billboards play an important role in advertising; nevertheless a lot of people only perceive them unconsciously and thus cannot remember the advertising message. With MirrorBoard we want to grab people's attention and enhance memorization of the product by letting people interact with the billboard or by integrating the observer into the scene itself. Such posters might act as gateways to mobile services which allow the user seamless and natural interaction with the poster. This paper presents scenarios showing how people can interact with MirrorBoard and describes how such a system can be implemented. To evaluate a prototype system we conducted a user study, the results of which will also be discussed.