  A variety of stellar explosions powered by black hole accretion are
discussed. All involve the failure of neutrino energy deposition to launch a
strong supernova explosion. A key quantity which determines the type of high
energy transient produced is the ratio of the engine operation time, $\rm
t_{engine}$, to the time for the explosion to break out of the stellar surface,
$\rm t_{bo}$. Stars with sufficient angular momentum produce collapsars --
black holes accreting rapidly through a disk -- in their centers. Collapsars
can occur in stars with a wide range of radii depending on the amount of
pre-collapse mass loss. The stellar radius and jet properties determine the
degree of beaming of the explosion. In some cases the stellar envelope serves
to focus the explosion to narrow beaming angles. The baryon loading of various
models for classical GRBs formed in massive stars is examined and the
consequences are explored. For $\rm t_{engine} > t_{bo}$, highly relativistic
outflow is possible and classical GRBs accompanied by supernovae can be
produced. In other cases hyper-energetic, asymmetric supernovae are produced.
Longer GRBs ($t \gtaprx 100 \s$) can be produced by fallback following a weak
neutrino-driven supernova explosion.
