CLNUPlot
This system is no longer being maintained (at least not by Gary King).

CLNUPlot connects Common Lisp to GNUPlot. More information about this plotting library can be found on its project page.

Download

ASDF-install package (obsolete) http://common-lisp.net/project/clnuplot/clnuplot.tar.gz

This is another one of Gary King's projects.