SciLabdeveloped by a scientific consortium based in France, is an open source MatLab clone that can ingest MatLab code. Worth a look if you are MatLab savvy and want a open source alternative. Also has a simulation module.

Gephi is a similarly supported open source graph analysis software for complex systems and dynamic networks.

Tableau an interesting interactive data display tool.

This one is a pay product, but looks interesting

Flying logic (Hat tip to Chris Weuve) planning and course of action analysis tool.

Check them out!