Fimex is a the File Interpolation, Manipulation, and EXtraction library for gridded geospatial data. It converts between different, extensible data formats (currently netcdf, NcML, grib1/2, metgm, wdb, and felt). It enables you to change the projection and interpolation of scalar and vector grids. It makes it possible to subset the gridded data and to extract only parts of the files. For simple usage, Fimex also comes with the command line program fimex.
FreeCAD is a CAx RAD based on OpenCASCADE, Qt4, and Python. It features some key concepts like Macro recording, Workbenches, and the ability to run as a server. It's also platform-independent. It is is fully scriptable and designed to be easily extensible; only the core functionality is embedded into the core libraries, but all further functionality like support of triangle meshes, CAM, FEM, etc. is implemented in extension modules. Normally, such a module is divided into an 'App' part containing the data structures and algorithms and a 'GUI' containing the graphical representation of data structures, dialogs, workbenches, etc.
Jmol is a Free, Open Source molecule viewer and editor. It is a collaboratively developed visualization and measurement tool for chemical scientists. Jmol is an active project, and there are new features being added to it on a daily basis. Users are encouraged to modify it to fit their needs and to contribute their changes to the project.