Time banking facilitates generalized reciprocity among neighbors by rewarding contributions in proportion to the time entailed in contributing. Contributions can be person-to-person services, such as driving another person to an appointment. They can also be co-productions, in which the provider and recipient jointly enact a service, such as giving/receiving a guitar lesson. Co-production is an important category of time banking interaction; it has been identified as a key to strengthening the core economy of home, family, neighborhood and community, and is becoming integrated into government social service schemes. As part of a requirements analysis for mobile timing banking infrastructures, we identified and analyzed co-production scenarios. Our objective is to contribute to the social movements of co-production of social services and of time banking through designing and developing a socio-technical infrastructure that mutually leverages both to build up the core economy and to enable societal-scale time banking.