(I sent this via comp.lang.ruby in June, but it didn't seem to
make it to the mailing list..)

For everything we can.

Lately, I managed to use it to typeset the survey results
from the Edward Tufte's Presenting Data and Information class
NASA Langley hosted last January.

The gory details are at

  http://www.engin.umich.edu/~kleb/TufteSurvey/

Please critique the code if you're up to it.  It wasn't built
test-first, so it is quite sloppy.  It was also my first foray
into writing LaTeX with Ruby and hooking into XML.

Regardless, it was a joy: Thanks Matz!


Other uses we've found for Ruby that I can immediately recall:

  test/unit for C-code test-first development

  rolled our own xUnit testing framework for Fortran 9X

  documenting Fortran 9X source via a plugin to Rdoc (thanks Dave!)

  automating one of our computational fluid dynamics (CFD) codes
  so that we can analyze shuttle tile damage quickly and reliably

  Fortran Code runners

  Fortran makefile dependency generation

  automatically convert our http://fun3d.larc.nasa.gov/ CFD Fortran
  code to complex variables for design optimization

  Beowulf cluster monitoring scripts

  CVS helper scripts,  e.g., coding standard commit sentinel, code
  clean-up, log summaries, plot usage generation, rewind files, and
  dependency graph generation via Graphviz.

  Refactoring Fortran code

  Continuous integration and build scripts

  CFD for simple model equations (code available upon request)

Regards,
-- 
Bil Kleb, Hampton, Virginia