The recent advances in membrane protein crystallography have provided extremely valuable structural information of the superfamily of GPCRs (G-protein-coupled receptors). This has been particularly true for a few receptors whose structure was solved several times under different biochemical conditions. It follows that the mechanisms of receptor conformational equilibrium and related dynamic events can be explored by computational simulations. In the present article, we summarize our recent understanding of several dynamic features of GPCRs, accomplished through the use of MD (molecular dynamics) simulations. Our pipeline for the MD simulations of GPCRs, implemented in the web service http://gpcr.usc.es, is updated in the present paper and illustrated by recent applications. Special emphasis is put on the A2A adenosine receptor, one of the selected cases where crystal structures in several conformations and conditions exist, and on the dimerization process of the CXCR4 (CXC chemokine receptor 4).