  We present a package for Mathematica that facilitates the numerical
computation of the quasinormal mode (QNM) spectrum of a black hole/black brane.
Requiring as input only the QNM equation(s), the application of a single
Mathematica function will compute the spectrum efficiently, by discretizing the
equation(s) and solving the resulting generalized eigenvalue equation. It is
applicable to a large variety of black holes, independent of their asymptotics.
The package comes fully documented and with several tutorials. Here we present
a self-contained review of the method and consider several applications. We
illustrate the method in the simplest case of scalar QNMs of a Schwarzschild
black brane in anti-de Sitter. Then we go on to look at the scalar QNMs of the
Schwarzschild black hole in de Sitter, in anti-de Sitter and in asymptotically
flat spacetimes, finding a novel infinite set of purely imaginary modes in the
first case. We also derive the QNM equations for a generic
Einstein-Maxwell-scalar background and use these to compute the QNMs of the
asymptotically anti-de Sitter Reissner-Nordstr\"{o}m black brane, as a further
illustration and check of the method.
