  We present the Coordinated Synoptic Investigation of NGC 2264, a continuous
30-day multi-wavelength photometric monitoring campaign on more than 1000 young
cluster members using 16 telescopes. The unprecedented combination of
multi-wavelength, high-precision, high-cadence, and long-duration data opens a
new window into the time domain behavior of young stellar objects. Here we
provide an overview of the observations, focusing on results from Spitzer and
CoRoT. The highlight of this work is detailed analysis of 162 classical T Tauri
stars for which we can probe optical and mid-infrared flux variations to 1%
amplitudes and sub-hour timescales. We present a morphological variability
census and then use metrics of periodicity, stochasticity, and symmetry to
statistically separate the light curves into seven distinct classes, which we
suggest represent different physical processes and geometric effects. We
provide distributions of the characteristic timescales and amplitudes, and
assess the fractional representation within each class. The largest category
(>20%) are optical "dippers" having discrete fading events lasting ~1-5 days.
The degree of correlation between the optical and infrared light curves is
positive but weak; notably, the independently assigned optical and infrared
morphology classes tend to be different for the same object. Assessment of flux
variation behavior with respect to (circum)stellar properties reveals
correlations of variability parameters with H$\alpha$ emission and with
effective temperature. Overall, our results point to multiple origins of young
star variability, including circumstellar obscuration events, hot spots on the
star and/or disk, accretion bursts, and rapid structural changes in the inner
disk.
