Eliot Quataert presents a public talk at UC Berkeley on February 21st, 2009, in celebration of the International Year of Astronomy, as part of the series described at astro.berkeley.edu/iya . Dr. Quataert begins by describing what black holes are (and what they are not!). He then discusses how big black holes at the centers of galaxies are discovered, how they form, and how they give rise to some of the most remarkable and bizarre phenomena in the universe. Videography and editing by Chris Klein. This video is released under a Creative Commons Attribution-Noncommercial-Share Alike 3.0 License - creativecommons.org/licenses/by-nc-sa/3.0/us