directly measured distribution of kick velocities, we would expect less than 1% of all pulsars born in a globular cluster to remain. But this is not the case—globular clusters contain many pulsars, some in excess of 1000. The number can be improved somewhat if one allows a fraction of the kick momentum to be transferred to a binary partner. In this case, perhaps 6% ought to survive, but this is not sufficient to explain the discrepancy. This appears to imply that some large set of pulsars receive virtually no kick at all while others receive a very large kick. It would be difficult to see this bimodal distribution directly because many speed measurement schemes only put an upper limit on the object's speed. If it is true that some pulsars receive very little kick, this might give us insight into the mechanism for pulsar kicks, since a complete explanation would have to predict this possibility. Theories Many hydrodynamical theories have been proposed, all of which attempt to explain the asymmetry in supernova using convection or mechanical instabilities in the presupernova star. Perhaps the easiest to understand is the "overstable g-mode". In this theory, we first assume that the core is pushed slightly to one side, off center from the star. This increases the pressure in the nearby silicon and oxygen shells of the star. Since the rate of nuclear reactions in these shells is very sensitively dependent on pressure, the added pressure results in a large release of energy, and the core is pushed back the other way. This in turn adds greater pressure on the other side, and we find that the core begins to oscillate. It has been shown that many such modes are overstable in heavy stars, that is, a small perturbation becomes large over time. When the star explodes, the core has additional momentum in some direction, which we observe as the kick. It has been proposed that hydrodynamical models can explain the bimodal distribution, through a "dichotomous kick scenario" in which the envelope of the presupernova star is stolen by a binary companion, dampening mechanical instabilities and thus reducing the resulting kick. There are two main neutrino driven kick scenarios, relying on the parity violation of neutrino interactions to explain an asymmetry in neutrino distribution. The first uses the fact that in the presence of a magnetic field, the direction that a neutrino is scattered