It has been shown that collaborative musical interfaces encourage novice users to explore the sound space and promote their participation as music performers. Nevertheless, such interfaces are generally physically situated and can limit the possibility of movements on the stage, a critical factor in live music performance. In this paper we introduce the Drummer, a networked digital musical interface that allows multiple performers to design and play drum kits simultaneously while, at the same time, keeping their ability to freely move on the stage. The system consists of multiple Nintendo DS clients with an intuitive, user-configurable interface and a server computer which plays drum sounds. The Drummer Machine, a small piece of hardware to augment the performance of the Drummer, is also introduced.