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!