  We have undertaken a long-term project, Planets in Stellar Clusters Extensive
Search (PISCES), to search for transiting planets in open clusters. NGC 2158 is
one of the targets we have chosen -- an intermediate age, populous, rather
metal poor cluster. In this paper we present the results of a search for
variable stars in the data from the first season of monitoring at the FLWO 1.2
m telescope. This is the first variability search ever conducted in this
cluster. We present a catalog of 57 variable stars, most with low amplitude
variability. Among the variables is a cataclysmic variable (CV) which underwent
a 2.5 mag outburst. If it is a member of NGC 2158, this would be the fourth CV
known in an open cluster. We have also found five delta Scuti stars, three of
which we have two or more detectable modes of pulsation. Of the 57 variables
discovered, 28 have R-band amplitudes of 5% or below. Six of those vary at or
below the 2% level, including one with 0.08% variability.
