Room-temperature ionic liquids (IL), i.e., organic ionic compounds whose melting temperature is below 100 C, are currently the focus of an intense and broad research effort because of their remarkable potential for applications coupled to favourable environmental properties. Furthermore, IL represent an important class of high density, highly correlated Coulomb fluids stable at or near ambient conditions, adding a fundamental flavor to the many reasons of interest in these systems. Maintaining the present rate of progress in applications and in the basic science of IL increasingly requires the close integration of experimental and computational methods. Simulation, in particular, has provided valuable insight into the microscopic properties of these complex materials, and played a major role in shaping our view of their structure and dynamics. On the other hand, the vast amount of experimental information on the phase diagram, the density, diffusion and viscosity coefficients, and interfacial properties of IL provides an unprecedented opportunity to test our potential energy approximations, and to expand our understanding of inter-particle interactions in molecular condensed phases.