  We present a generally-covariant and parity-invariant "zwei-dreibein" action
for gravity in three space-time dimensions that propagates two massive spin-2
modes, unitarily, and we use Hamiltonian methods to confirm the absence of
unphysical degrees of freedom. We show how zwei-dreibein gravity unifies
previous "3D massive gravity" models, and extends them, in the context of the
AdS/CFT correspondence, to allow for a positive central charge consistent with
bulk unitarity.
