We present a rendezvous based medium access control (MAC), culled ArDeZ, for use in sensor networks. ArDeZ is a TDMA based medium access scheme that does not rely on strict time slot positioning and assignments, making ArDeZ easily deployable in large sensor networks without having to adhere to strict time slot boundaries. ArDeZ establishes two independent peer-to-peer time channels between nodes, and these channels do not necessarily have the same duty cycle. Each channel has a set of rendezvous periods associated with it that are generated from a seed exchanged during the setup process. Further, the duration and frequency of each channel's rendezvous periods are easily changed by an application for each link on a given path, thereby allowing the application to balance traffic and energy requirements. We have implemented ArDeZ in the ns-2 simulator, and our results show that ArDeZ is capable of very low power consumption.