Constructor
Java applet that animates two dimensional models made out of masses and springs.

MCSim Simulation Software
Statistical or simulation models, Monte Carlo simulations, and Bayesian inference through Markov Chain Monte Carlo simulations. Written in C, free download under GPL.

SimGrav Cosmo Lab
A cosmic laboratory for modelling gravitation interactions. Windows binaries free to download, source code on request.

Tacoma Narrows Bridge Simulation
A numerical simulation of the collapse of the Tacoma Narrows bridge by Cillian ÓTuama. Download standalone executable for Windows.