  We review various modified gravities considered as gravitational alternative
for dark energy. Specifically, we consider the versions of $f(R)$, $f(G)$ or
$f(R,G)$ gravity, model with non-linear gravitational coupling or
string-inspired model with Gauss-Bonnet-dilaton coupling in the late universe
where they lead to cosmic speed-up. It is shown that some of such theories may
pass the Solar System tests. On the same time, it is demonstrated that they
have quite rich cosmological structure: they may naturally describe the
effective (cosmological constant, quintessence or phantom) late-time era with a
possible transition from decceleration to acceleration thanks to gravitational
terms which increase with scalar curvature decrease. The possibility to explain
the coincidence problem as the manifestation of the universe expansion in such
models is mentioned. The late (phantom or quintessence) universe filled with
dark fluid with inhomogeneous equation of state (where inhomogeneous terms are
originated from the modified gravity) is also described.
