This chapter provides a number of examples of numerical simulations in NMR. Main focus is on advanced simulations in solid-state NMR using the widely used SIMPSON simulation package. The chapter starts with introductory examples providing a gentle introduction to SIMPSON and various concepts of solid-state NMR. Following the introduction is a demonstration on how SIMPSON can interact with SIMMOL for setting up spin systems of protein spin systems. Finally, we demonstrate how the versatile Tcl interface of SIMPSON can be used to expand the capabilities of SIMPSON, here exemplified by simulations of chemical exchange. The examples demonstrate that SIMPSON may be regarded a “virtual NMR spectrometer”.