  I provide an incomplete inventory of the astronomical variability that will
be found by next-generation time-domain astronomical surveys. These phenomena
span the distance range from near-Earth satellites to the farthest Gamma Ray
Bursts. The surveys that detect these transients will issue alerts to the
greater astronomical community; this decision process must be extremely robust
to avoid a slew of ``false'' alerts, and to maintain the community's trust in
the surveys. I review the functionality required of both the surveys and the
telescope networks that will be following them up, and the role of VOEvents in
this process. Finally, I offer some ideas about object and event
classification, which will be explored more thoroughly by other articles in
these proceedings.
