CarpetCode - A mesh refinement driver for the Cactus code; the primary application is the simulation of black hole spacetimes. Form Symbolic Manipulation System - A free software package for manipulating tensors (abstract index notation) and other multi-component objects; highly suitable for calculations in general relativity and related theories such as supergravity. Documentation, course material, and possibilities for download. GRTensorII - A computer algebra package for performing differential geometry calculations. Demonstrations of the package's applications to general relativity. LORENE (Langage Objet pour la RElativite NumeriquE) - Provides a set of C++ classes to solve various problems arising in numerical relativity and other areas of computational astrophysics. openGR - An open framework for large numerical simulations in general relativity. Riemann Package for Maple - Package written in Maple for calculating tensor components in General Relativity and performing some abstract tensor manipulation; suitable for calculations in general relativity and for quantum field theory in curved spacetime. Features brief description, download for Maple V and for Maple 6 or higher, and examples. Whisky - A code to evolve the equations of hydrodynamics in curved spacetime (relativistic numerical hydrodynamics). The Cactus Code - A modular manageable high-performance 3D tool for Numerical Relativity. Ricci - A Mathematica package for doing tensor calculations in differential geometry and general relativity.