  The K2 mission is targeting large numbers of nearby (d<100 pc) GKM dwarfs
selected from the SUPERBLINK proper motion survey (mu>40 mas yr^-1, V<20).
Additionally, the mission is targeting low-mass, high proper motion stars
associated with the local (d<500 pc) Galactic halo population also selected
from SUPERBLINK. K2 campaigns 0 through 8 monitored a total of 27,382 of these
cool main-sequence stars. We used the auto-correlation function to search for
fast rotators by identifying short-period photometric modulations in the K2
light curves. We identified 508 candidate fast rotators with rotation periods
<4 days that show light curve modulations consistent with star spots. Their
kinematics show low average transverse velocities, suggesting they are part of
the young disk population. A subset (13) of the fast rotators are found among
those targets with colors and kinematics consistent with the local Galactic
halo population and may represent stars spun up by tidal interactions in close
binary systems. We further demonstrate the M dwarf fast rotators selected from
the K2 light curves are significantly more likely to have UV excess, and
discuss the potential of the K2 mission to identify new nearby young GKM dwarfs
on the basis of their fast rotation rates. Finally, we discuss the possible use
of local halo stars as fiducial, non-variable sources in the Kepler fields.
