[url=http://www.gnuplot.info/]Gnuplot[/url]: Gnuplot  is a portable command-line driven interactive data and function plotting utility for UNIX, IBM OS/2, MS Windows, DOS, Macintosh, VMS, Atari and many other platforms.

[url=http://workbench.concord.org/]Molecular Workbench[/url]:The Molecular Workbench (MW) is a free, open-source tool that delivers visual, interactive simulations for teaching and learning science.

[url=http://audacity.sourceforge.net/]Audacity[/url]: Free Audio Editor and Recorder/Audio editor for recording, slicing, and mixing audio.