This is EvilFinder, copyright by Michal Zalewski <lcamtuf@coredump.cx>.

  This tiny program goes thru a database of numerologically significant
  positive integers (dates, magic numbers, etc) in the evilnumbers.dat
  file, and tries to transform a given input in a way that would yield
  one of arch-evil numbers, such as 666, thus proving that the subject
  is evil. This is useful for proving that Windows, Linux, Bill Gates,
  Jerry Springer or you are in fact the devil himself.

  The program is written for a CGI script, so it returns HTML. Input 
  is taken from the environment variable QUERY_STRING_UNESCAPED after
  first =, for example:

  QUERY_STRING_UNESCAPED='_=hello' ./ef | lynx -dump -force_html /dev/stdin

  Of course, this is not very sexy, but c'mon. It's a web application.