In this paper, we present a game of dice that combines multi-party communication with a tangible interface. The game has been used as a testbed to study typical conversational behavior patterns in interactions between human users and synthetic agents. In particular, we were interested in the question to what extent the interaction with the agent can be considered as natural. As an evaluation criterion, we propose to investigate whether the communicative behaviors of humans differ when conversing with an agent as opposed to conversing with other humans.