  I present results of two-dimensional general relativistic hydrodynamical
simulations of constant specific angular momentum tori orbiting around a
Schwarzschild black hole. After introducing axisymmetric perturbations, these
objects either become unstable to the runaway instability or respond with
regular oscillations. The latter, in particular, are responsible for
quasi-periodic bursts of accretion onto the black hole as well as for the
emission of intense gravitational radiation, with signal-to-noise ratios at the
detector which are comparable or even larger than the typical ones expected in
stellar-core collapse.
