k-mean classifier.  use like so:

MHARTZLER-SNOW:kmean matt$ cat titles.txt | ruby kmean.rb 3 10

["apple layoffs affect workforce", "apple rules after layoffs", "apple down after layoffs", "layoffs from apple a sign"]

["asfd foobar", "dogs and cats angry", "will dogs and cats ruin everything", "dogs and cats rebel"]

["does anybody want microsoft stock", "microsoft sells some stock", "microsoft stock prices", "when will microsoft stock fall"]