  The quark-gluon plasma created in a relativistic heavy-ion collisions
possesses a sizable pressure anisotropy in the local rest frame at very early
times after the initial nuclear impact and this anisotropy only slowly relaxes
as the system evolves. In a kinetic theory picture, this translates into the
existence of sizable momentum-space anisotropies in the underlying partonic
distribution functions, <p_L^2> << <p_T^2>. In such cases, it is better to
reorganize the hydrodynamical expansion by taking into account momentum-space
anisotropies at leading-order in the expansion instead of as a perturbative
correction to an isotropic distribution. The resulting anisotropic
hydrodynamics framework has been shown to more accurately describe the dynamics
of rapidly expanding systems such as the quark-gluon plasma. In this
proceedings contribution, I review the basic ideas of anisotropic
hydrodynamics, recent progress, and present a few preliminary phenomenological
predictions for identified particle spectra and elliptic flow.
