  Black holes are popping up all over the place: in compact binary X-ray
sources and GRBs, in quasars, AGNs and the cores of all bulge galaxies, in
binary black holes and binary black hole-neutron stars, and maybe even in the
LHC! Black holes are strong-field objects governed by Einstein's equations of
general relativity. Hence general relativistic, numerical simulations of
dynamical phenomena involving black holes may help reveal ways in which black
holes can form, grow and be detected in the universe. To convey the
state-of-the art, we summarize several representative simulations here,
including the collapse of a hypermassive neutron star to a black hole following
the merger of a binary neutron star, the magnetorotational collapse of a
massive star to a black hole, and the formation and growth of supermassive
black hole seeds by relativistic MHD accretion in the early universe.
