Abstract: Supermassive black holes create powerful jets of radiation and plasma particles that move close to the speed of light. The answers to the questions “how exactly are jets powered by energy extraction from a black hole” and “what are the processes that energize plasma particles” are crucial to understanding the observed activity. Recent years opened new spectacular observational windows into studying plasmas that emit observed light, including multi-wavelength observations of powerful flares and the black hole “shadow” by the Event Horizon Telescope. These exciting discoveries, as well as attempts to improve the understanding of the nature of the curved spacetime, call for a new level of quantitative understanding of plasma dynamics around black holes. In this talk, I will discuss recent progress in first-principles numerical modeling of processes that can power jets, flares and pair discharges near the black holes.