When exoplanets transit their parent stars, we are granted an unparalleled opportunity to detect their presence and study their bulk properties.  I will review recent analyses of data from the NASA Kepler Mission to deduce the rate of occurrence of small planets.  I will then present follow up measurements of the acceleration of a subset of the host stars, which allows us to estimate the planetary masses and hence densities.  Finally, I will discuss recent findings from the MEarth Project, which seeks to discover the most spectroscopically accessible terrestrial exoplanets.  Our recent discovery of a temperate rocky world orbiting the nearby small star LHS1140 provides an unprecedented opportunity to detect the molecules present in the atmosphere of a terrestrial exoplanet.