Far from being dark, black holes are at the heart of the most energetic and luminous phenomena observed in the universe, from quasars to gamma-ray bursts. In fact, black hole power has actually had a significant ecological impact on the universe, affecting how entire galaxies formed and evolved. Understanding how all this works requires understanding how gravitational binding energy is released as matter falls into the hole. The entire process is complex (turbulent radiation magnetohydrodynamics!), but the basic elements within the process involve some very cute physical principles, and I will focus on what we have recently learned about these in this talk.