  We present first results from a new, multiyear, time domain survey of young
stars in the North America Nebula complex using the Palomar Transient Factory.
Our survey is providing an unprecedented view of aperiodic variability in young
stars on timescales of days to years. The analyzed sample covers R_PTF =
13.5-18 and spans a range of mid-infrared color, with larger-amplitude optical
variables (exceeding 0.4 mag root-mean-squared) more likely to have
mid-infrared evidence for circumstellar material. This paper characterizes
infrared excess stars with distinct bursts above or fades below a baseline of
lower-level variability, identifying 41 examples. The light curves exhibit a
remarkable diversity of amplitudes, timescales, and morphologies, with a
continuum of behaviors that can not be classified into distinct groups. Among
the bursters, we identify three particularly promising sources that may
represent theoretically predicted short-timescale accretion instabilities.
Finally, we find that fading behavior is approximately twice as common as
bursting behavior on timescales of days to years, although the bursting and
fading duty cycle for individual objects often varies from year to year.
