Popular acceptance of the mp3 digital music standard has greatly increased the complexity of organizing and playing large music collections. Existing digital music systems do not adequately support exploration of a collection, nor do they cater to multi-user interaction in a social setting. In this paper, we present the design of a ubiquitous system that utilizes spatial visualization to support exploration and social interaction with a large music collection. Our interface is based on the interaction semantic of influence, which allows users to affect and control the mood of music being played without the need to select a set of specific songs. This design is inspired, to some extent, by Gavers work on ludic design. We implemented a prototype as a proof of concept of our design. User testing demonstrates that our system encourages participation and strengthens social cohesion. Our work contributes to interactive interface re-search in that it extends the utility of map-based visualization of digital music.