A list (Alphabetical) of software, I have used, for teaching, and others!

Calculix, FEA Program, Free and very versatile: http://www.calculix.de/

CBA, Software for shear force and bending moment diagrams of continuous beams: http://sourceforge.net/projects/cbeam/

Ftool, A structural analysis educational interactive tool: http://www.tecgraf.puc-rio.br/ftool/ftooleng.html

Frame3dd, Structural Analysis program, Static, Dynamic for 2D and 3D frames and trusses: http://frame3dd.sourceforge.net/

Freemind, mindmapping: http://freemind.sourceforge.net/wiki/index.php/Main_Page

GNOME: My desktop: (I use the classic desktop) http://www.gnome.org/ (moved out as of now)

GNUPlot: Basic Plotting program: http://www.gnuplot.info/

GNU Octave: For plotting and other mathematical computations: https://www.gnu.org/software/octave/

Matplotlib: For plotting data anything to everything: http://matplotlib.org/

Mendeley, Research made easy: http://www.mendeley.com/

OpenSees Parallel FEA Analysis specifically designed for Earthquake Analysis: http://opensees.berkeley.edu/

Phatch, Batch Processing of Photos: http://photobatch.stani.be/

Scilab, Replacement for Matlab: http://www.scilab.org/

Shotwell, Photo Library: http://www.yorba.org/projects/shotwell/

wxMaxima, Algebra! : http://andrejv.github.io/wxmaxima/