A helper for rails to create a tag cloud out a string of words (space delimited). Adapted the idea from here: http://snippets.dzone.com/posts/show/6027

rails-word_cloud-helper.rb

def word_cloud(words)
    wordcount = {}
    words.split(/\s/).each do |word| 
      word.downcase!
      if word.strip.size > 0
        wordcount[word.strip] = (wordcount.key?(word.strip)) ? (wordcount[word.strip] + 1) : 0
      end
    end
    
    s = []
    wordcount.each_value do |v|
      s << v
    end
    s = s.sort.reverse.slice(0,20)
    min, max = s.last, s.first
    ratio = 18.0 / (max - min)

    cloud = String.new
    wordcount.each_key do |word|
      font_size = (9 + (wordcount[word] * ratio))
      cloud += link_to word, search_path(:type => "tag", :term => word), :style => "font-size: #{font_size}pt;"
      cloud << " "
    end
    
    cloud    
  end