  We consider the possibility that D^0 - anti-D^0 mixing undergoes resonant
enhancement. Various scenarios are explored, including the potential effects of
nearby pseudoscalar or scalar quark-antiquark (Q - anti-Q) resonances as well
as of hybrid quark-antiquark-gluon Q - anti-Q G states. Assuming reasonable
values for the resonance parameters we find relatively sizeable contributions
from individual resonances to both \Delta m_D and \Delta \Gamma_D. We derive a
variant of the GIM cancellation mechanism for the resonance amplitudes and show
that broken SU(3) can allow for sizeable residual effects. Additional input
from meson spectroscopy and lattice gauge simulations will be needed to improve
the accuracy of these predictions.
