I posted last time about TeXmacs and remembered the plugins for using it to display output from some of the superb free maths packages (which sometimes lack a nice display).
The one I am excited about most is for SAGE. SAGE is written in python and leverages the hard work of the other projects (its motto is Building the Car Instead of Reinventing the Wheel). See the TeXmacs plugin here and some screenshots of SAGE here.
I will take a look at the code and see if I can contribute anything, it will be nice to get involved in a big project.