  We study the N=2 supersymmetric Chern-Simons quiver gauge theory recently
introduced in arXiv:0809.3237 to describe M2-branes on a cone over the
well-known Sasaki-Einstein manifold Q^{1,1,1}. For Chern-Simons levels
(k,k,-k,-k) we argue that this theory is dual to AdS_4 x Q^{1,1,1}/Z_k. We
derive the Z_k orbifold action and show that it preserves geometrical symmetry
U(1)_R x SU(2) x U(1), in agreement with the symmetry of the gauge theory. We
analyze the simplest gauge invariant chiral operators, and show that they match
Kaluza-Klein harmonics on AdS_4 x Q^{1,1,1}/Z_k. This provides a test of the
gauge theory, and in particular of its sextic superpotential which plays an
important role in restricting the spectrum of chiral operators. We proceed to
study other quiver gauge theories corresponding to more complicated orbifolds
of Q^{1,1,1}. In particular, we propose two U(N)^4 Chern-Simons gauge theories
whose quiver diagrams are the same as in the 4d theories describing D3-branes
on a complex cone over F_0, a Z_2 orbifold of the conifold (in 4d the two
quivers are related by the Seiberg duality). The manifest symmetry of these
gauge theories is U(1)_R x SU(2) x SU(2). We argue that these gauge theories at
levels (k,k,-k,-k) are dual to AdS_4 x Q^{2,2,2}/Z_k. We exhibit calculations
of the moduli space and of the chiral operator spectrum which provide support
for this conjecture. We also briefly discuss a similar correspondence for AdS_4
x M^{3,2}/Z_k. Finally, we discuss resolutions of the cones and their dual
gauge theories.
