  We show how generic off--diagonal cosmological solutions depending, in
general, on all spacetime coordinates can be constructed in massive gravity
using the anholonomic frame deformation method. Such metrics describe the late
time acceleration due to effective cosmological terms induced by nonlinear
off--diagonal interactions and graviton mass and include matter, graviton mass
and other effective sources modelling nonlinear gravitational and matter fields
interactions with polarization of physical constants and deformations of
metrics, which may explain certain dark energy and dark matter effects.
