  Context. In August 2010, the sudden optical brightening of two young stellar
objects, located in the North America/Pelican Nebula Complex, was announced.
Early observations indicated that these objects may belong to the FUor or EXor
class of young eruptive stars. The eruptions of FUors and EXors are often
explained by enhanced accretion of material from the circumstellar disk to the
protostar. Aims. In order to determine the true nature of these two objects, we
started an optical and near-infrared monitoring program, and complemented our
data with archival observations and data from the literature. Methods. We plot
and analyze pre-outburst and outburst spectral energy distributions (SEDs),
multi-filter light curves, and color-color diagrams. Results. HBC 722
brightened monotonically in about two months, and the SED obtained during
maximum brightness indicates the appearance of a hot, single-temperature
blackbody. The current fading rate implies that the star will return to
quiescence in about a year, questioning its classification as a bone fide FUor.
The outburst of VSX J205126.1+440523 happened more gradually, but reached an
unprecedentedly high amplitude. At 2.5 months after the peak, its light curves
show a deep minimum, when the object was close to its pre-outburst optical
brightness. Further monitoring indicates that it is still far from being
quiescent. Conclusions. The shape of the light curves, the bolometric
luminosities and accretion rates suggest that these objects do not fit into the
classic FUor group. Although HBC 722 exhibit all spectral characteristics of a
bona fide FUor, its luminosity and accretion rate is too low, and its timescale
is too fast compared to classical FUors. VSX J205126.1+440523 seems to be an
example where quick extinction changes modulate the light curve.
