  We present a multi-year survey aimed at collecting (1) high-precision (~5
milli-mag), (2) fast-cadence (~3 min), and (3) relatively long duration (~10
days) multi-band photometric series. The goal of the survey is to discover and
characterize efficiently variable objects and exoplanetary transits in four
fields containing five nearby open clusters spanning a broad range of ages.
More in detail, our project will (1) constitute a preparatory survey for
HARPS-N@TNG, which will be used for spectroscopic follow-up of any target of
interest that this survey discovers or characterizes, (2) measure rotational
periods and estimate the activity level of targets we are already monitoring
with HARPS and HARPS-N for exoplanet transit search, and (3) long term
characterization of selected targets of interest in open clusters within the
planned K2 fields. In this first paper we give an overview of the project, and
report on the variability of objects within the first of our selected fields,
which contains two open clusters: M 35 and NGC 2158. We detect 519 variable
objects, 273 of which are new discoveries, while the periods of most of the
previously known variables are considerably improved.
