SimPack is a collection of C and C++ libraries and executable programs for computer simulation. In this collection, several different simulation algorithms are supported including discrete event simulation, continuous simulation and combined(multimodal) simulation. The purpose of the SimPack toolkit is to provide the user with a set of utilities that illustrate the basics of building a working simulation from a model description. We demonstrate that special purpose simulation programming languages can be easily constructed using language translation software with the SimPack utilities which act as the “assembly language.” We present several different dynamical system model forms and overview the methods used in SimPack for executing these models. SimPack includes some fairly extensive simulation facilities, and is in use by various instructors, researchers and industrial analysts for their modeling and simulation experiments.