In contrast with work focusing on routing problems in mobile ad hoc networks, this work addresses the problem of system configuration in such networks. In particular, we are interested in ways to instantiate the configuration infrastructure -- naming, addressing, authentication, and key distribution -- needed to establish small-to-medium scale ad hoc networks supporting collaborative applications. We argue that, in such spontaneous networks, much of the necessary infrastructure can be derived from the face-to-face human interactions that these networks are intended to facilitate. This approach has the additional advantage of being intuitive for the non-expert user.