104: Calc -- poor man's Mathematica within Emacs

  Author: Dave Gillespie <daveg@csvax.cs.caltech.edu>
  Latest version: 2.02c
  Anonymous FTP:
    ftp://prep.ai.mit.edu/pub/gnu/calc-2.02c.tar.gz
  NOTE: Unlike Wolfram Research, Dave has never threatened to sue
        anyone for having a program with a similar command language to
        Calc.  :-)