  We discuss various types of exotic (non-standard) singularities in the
Universe: a Big-Rip (BR or type I), a Sudden Future Singularity (SFS or type
II), a Generalized Sudden Future Singularity, a Finite Scale Factor singularity
(FSF or type III), a Big-Separation (BS or type IV) and a $w$-singularity. They
are characterized by violation of all or some of the energy conditions which
results in a blow-up of all or some of the physical quantities: the scale
factor, the energy density, the pressure, and the barotropic index. We relate
the emergence of these singularities with physical theories (superstring,
brane, higher-order gravity, loop quantum cosmology). We show how the models
involving exotic singularities may serve as dark energy by applying the
observational data. In particular, we show that some of these exotic
singularities (though being of a weak type according to relativistic
definitions) may occur in the near future of the universe.
