20-sim is a modeling and simulation program that runs under Microsoft Windows. With 20-sim you can simulate the behavior of dynamic systems, such as electrical, mechanical and hydraulic systems or any combination of these.
BizAgi BPMN Process Modeler is a freeware application that you can download from the Internet and use in a desktop or portable computer. It is very easy to use; in a matter minutes you will be able to begin defining your processes and collaborate with other people in your organization.
The best graphing program so far. It started on the Macintosh. The program has been around for decades and simply rocks. Unfortunately, Synergy software hasn't planned a linux version of their application.
Netdraw is a graph visualization and analysis program particularly suited for social network analysis. It is written by Steve Borgatti and can be downloaded and used for free (it is closed source though).
SMART Ideas™ concept-mapping software brings the power of visual learning to your classroom. It helps students visualize and analyze complex ideas by building multilevel interactive maps. This fun, colorful software enables students to conceptualize information more quickly.