  We present a kinematic study of the Orion Nebula Cluster based upon radial
velocities measured by multi-fiber echelle spectroscopy at the 6.5 meter MMT
and Magellan telescopes. Velocities are reported for 1613 stars, with
multi-epoch data for 727 objects as part of our continuing effort to detect and
analyze spectroscopic binaries. We confirm and extend the results of Furesz et
al. showing that the ONC is not relaxed, consistent with its youth, and that
the stars generally follow the position-velocity structure of the moderate
density gas in the region, traced by $^{13}$CO. The additional radial
velocities we have measured enable us to probe some discrepancies between
stellar and gaseous structure which can be attributed to binary motion and the
inclusion of non-members in our kinematic sample. Our multi-epoch data allow us
to identify 89 spectroscopic binaries; more will be found as we continue
monitoring. Our results reinforce the idea that the ONC is a cluster in
formation, and thus provides a valuable testing ground for theory. In
particular, our observations are not consistent with the quasi-equilibrium or
slow contraction models of cluster formation, but are consistent with cold
collapse models.
