We study collections of rotatory motors confined to 2-dimensional
manifolds. The rotational motion induces a repulsive hydrodynamic
interaction between motors leading to a non-trivial collective
behavior. For high rotation speed motors should arrange on a
triangular lattice exhibiting crystalline order. At low speed they
form a disordered phase where diffusion is enhanced by velocity
fluctuations. In confining geometries and under suitable boundary
conditions motor-generated flow might enhance left-right symmetry
breaking transport. All these effects should be experimentally
observable for motors driven by external fields and for dipolar
biological motors embedded into lipid membranes in a viscoelastic
solvent.