  We report the results of a diffraction-limited, photometric variability study
of the central 5"x5" of the Galaxy conducted over the past 10 years using
speckle imaging techniques on the W. M. Keck I 10 m telescope. Within our
limiting magnitude of mK < 16 mag for images made from a single night of data,
we find a minimum of 15 K[2.2 micron]-band variable stars out of 131 monitored
stars. The only periodic source in our sample is the previously identified
variable IRS 16SW, for which we measure an orbital period of 19.448 +- 0.002
days. In contrast to recent results, our data on IRS 16SW show an asymmetric
phased light curve with a much steeper fall-time than rise-time, which may be
due to tidal deformations caused by the proximity of the stars in their orbits.
We also identify a possible wind colliding binary (IRS 29N) based on its
photometric variation over a few year time-scale which is likely due to
episodic dust production. None of the 4 LBV candidates in our sample show the
characteristic large increase or decrease in luminosity, however, our time
baseline is too short to rule them out as LBVs. Among the remaining variable
stars, the majority are early-type stars and three are possibly variable due to
line of sight extinction variations. For the 7 OB stars at the center of our
field of view that have well-determined 3-dimensional orbits, we see no
evidence of flares or dimming of their light, which limits the possibility of a
cold, geometrically-thin inactive accretion disk around the supermassive black
hole, Sgr A*.
