Ruby script to check if you are eligible to log the "Know your local cacher". I've used in particular on http://coord.info/GC447Q2, but it should be easily adaptible to other similar caches. It will print a list of all cache owners of which you have logged at least three caches (of a certain) kind.

know-your-local-cachers.rb

# 
# Installation instructions for Nokogiri can be found at
# http://nokogiri.org/tutorials/installing_nokogiri.html
require 'nokogiri'
 
#
# Usage: ruby #{$0} /path/to/MyFinds.gpx
if ARGV.size == 0
  puts "Usage: ruby #{$0} /path/to/MyFinds.gpx"
  exit 1
end
 
xml = Nokogiri::XML(File.open(ARGV[0]))

ns = {
  'gpx' => 'http://www.topografix.com/GPX/1/0',
  'groundspeak' => "http://www.groundspeak.com/cache/1/0/1"
}

cachers = {}

xml.xpath("//groundspeak:cache", ns).each do |cache|
  owner = cache.xpath("./groundspeak:owner", ns).text
  type = cache.xpath("./groundspeak:type", ns).text
  code = cache.parent.xpath("./gpx:name", ns).text

  # This particular cache only allows certain caches
  # to be counted towards the total.
  if type == "Traditional Cache" or
      type == "Unknown Cache" or
      type == "Multi-cache"
    if not cachers.has_key? owner
      cachers[owner] = {}
    end
    
    cachers[owner][type] = code
  end
end

n = 0
cachers.each_pair do |key, value|
  if value.size >= 3
    n = n + 1
    puts "Cacher: #{key}"
    value.each_pair do |type, code|
      puts "#{type}: http://coord.info/#{code}"
    end
  end
end 


if n >= 15
  puts "Matches == #{n} (QUALIFIED)"
else
  puts "Matches == #{n} (NOT QUALIFIED)"
  puts "======"
  puts "Candidates (2 caches)"
  cachers.each_pair do |key, value|
    if value.size == 2
      puts "Cacher: #{key}"
      value.each_pair do |type, code|
        puts "#{type}: http://coord.info/#{code}"
      end
    end
  end 
end