Once thought extreme oddities, quasars - accreting supermassive black holes at the centers of galaxies - are currently understood to be fundamental in galaxy formation and evolution. Furthermore, quasars are now proving to be superb probes helping us trace and elucidate the geometry and cosmology of the Universe. In this talk, I will introduce and give an update on two projects, one using the SDSS telescope and one using the Spitzer Space Telescope. Both projects are specifically designed to find quasars and perform a full census of the supermassive black holes population.