A brief popular review is presented of physical phenomena in MHD plasma generators of electric power. The interaction between a current of weakly ionized gas and a transverse magnetic field is described. Qualitative explanations are given of the leading instabilities of this current and of certain phenomena near the electrodes. The characteristic properties of the plasma in MHD generators with nonequilibrium conductivity are noted. They include ionization turbulence, motion of the ionization front through a weakly ionized gas, and its stabilization at entry into the MHD duct. Data characterizing the scientific and technological achievements in the development of MHD generators are cited.