Crystallography is at the forefront of methods for obtaining macromolecular structural data, but it has traditionally focused on providing a single, "best-fit" static structure of the molecule. Molecular dynamics offers the potential for time-resolved investigation of molecules at an atomic level, but requires experimental data for accurate parametrization and validation of the underlying energy potential. We present recent efforts at integrating crystallography and molecular dynamics in a way that is beneficial to both fields. First, we present the development of methods for all-atom, explicit solvent simulations of macromolecular crystals. Simulations provide us with a window on the highly dynamic and heterogeneous structural landscape of crystals that at the same time is fully consistent with the time and space-averaged diffraction experiment. A fascinating interplay between experiment and computation leads to more accurate interpretation of both the diffraction and molecular dynamics data. Second, we present the integration of molecular dynamics into the crystal refinement workflow. The Phenix crystal refinement program uses Amber to generate improved structures that take account of electrostatic forces, while Phenix integrated with AFITT leads to chemically more sensible ligand geometries.