The central densities of neutron stars are the highest known in the Universe, so mass and radius measurements of pulsars give us unique insights into the physics of matter at extreme densities. High-precision timing measurements in the radio have provided extremely constraining mass measurements, including iron-clad results that pulsars can be >2 Msun. Such systems strongly constrain the equation of state of neutron star matter. Amazingly, we can often measure these masses "for free" as part of other projects, such as pulsar timing array (e.g. NANOGrav) observations or searches for exotic pulsar systems in globular clusters. In this talk I'll describe how pulsar timing can provide robust mass measurements of neutron stars, and I'll show you some amazing new pulsar systems where we are doing just that.
