The Transient Gravitational-Wave Sky
  Interferometric detectors will very soon give us an unprecedented view of the
gravitational-wave sky, and in particular of the explosive and transient
Universe. Now is the time to challenge our theoretical understanding of
short-duration gravitational-wave signatures from cataclysmic events, their
connection to more traditional electromagnetic and particle astrophysics, and
the data analysis techniques that will make the observations a reality. This
paper summarizes the state of the art, future science opportunities, and
current challenges in understanding gravitational-wave transients.
