Following the work of Aharony, Bergman, Jafferis and Maldacena, a great effort has been made to understand the 3d conformal gauge theories describing M2-branes at conical singularities. Special attention has been directed to N=2 supersymmetric AdS4/CFT3 pairs arising from M2-branes at toric CY 4-folds, where powerful algebraic techniques are available. After reviewing some results concerning brane tilings, the relation between the toric CY3 and CY4 moduli spaces of 4d and 3d toric quiver gauge theories, and M-theory/type IIA duality, I will explain how flavours naturally arise in this framework, and how their matter content and superpotential couplings to bifundamental fields are encoded in geometric data. Quantum effects are crucial in computing the moduli spaces of such flavoured quiver gauge theories. Any quiver Chern-Simons (CS) theory of the kind considered in the AdS4/CFT3 literature so far can be obtained by coupling a 3d gauge theory with the same quiver diagram but no CS terms to chiral flavours, and integrating them out via a real mass term.