  We explore multi-component dark matter models where the dark sector consists
of multiple stable states with different mass scales, and dark forces coupling
these states further enrich the dynamics. The multi-component nature of the
dark matter naturally arises in supersymmetric models, where both R parity and
an additional symmetry, such as a $Z_2$, is preserved. We focus on a particular
model where the heavier component of dark matter carries lepton number and
annihilates mostly to leptons. The heavier component, which is essentially a
sterile neutrino, naturally explains the PAMELA, ATIC and synchrotron signals,
without an excess in antiprotons which typically mars other models of weak
scale dark matter. The lighter component, which may have a mass from a GeV to a
TeV, may explain the DAMA signal, and may be visible in low threshold runs of
CDMS and XENON, which search for light dark matter.
