A User-Friendly visualization toolkit for machine learning: MLDemos. Extensible architecture, contains modules for classification (gaussian mixture models, kernel methods such as support vector machines, nearest neighbor, kernel PCA, boosting, multilayer perceptrons, linear classifiers), clustering (gaussian mixtures, kernel methods, k-means), regression, etc.

A complete X server implementation in Java which can run standalone or as an applet. It supports remote X and (using libjsch-java) X forwarded over SSH.

Pry is a powerful alternative to the standard IRB shell for Ruby. It is written from scratch to provide a number of advanced features, some of these include:

The SBMLToolbox provides a set of basic functions for reading, writing, manipulating, and simulating SBML (System Biology Meta Language) models. It is a free Open Source package on top of the libSBML with full compatibility to work with MATLAB and Octave alike and share models between the two systems.