It is usable both standalone (through a wrapper around the library written in Ruby) or as a library from within Common Lisp.
Download: http://bettong.net/files/projects/narcl/narcl-0.4.1.tar.bz2
Author: Urban Hafner
License: ???
NARCL
NARCL is short for Negative Association Rule Mining in Common Lisp and is an association data mining/machine learning/AI library and application.