Clustered computing environments, although becoming the predominant high-performance computing platform of choice, continue to grow in complexity. It is relatively easy to achieve good performance with real-world MPI applications on such platforms, but obtaining the best possible MPI performance is still an extremely difficult task, requiring painstaking tuning of all levels of the hardware and software in the system. The Open Tool for Parameter Optimization (OTPO) is a new framework designed to aid in the optimization of one of the key software layers in high performance computing: Open MPI. OTPO systematically tests large numbers of combinations of Open MPI's run-time tunable parameters for common communication patterns and performance metrics to determine the "best" set for a given platform. This paper presents the concept, some implementation details and the current status of the tool, as well as an example optimizing InfiniBand message passing latency by Open MPI.