Taking an Array of Hashes and turning them into key-value pairs using a style similar to ActiveRecord's dynamic finders.

dynamic_mapper.rb

class Array
  attr_accessor :dynamic_mapper_key, :dynamic_mapper_value

  def method_missing(method, *args, &block)
    if dynamic_mapper?(method)
      map_dynamically(method)
    else
      super
    end
  end

  def dynamic_mapper?(method)
    if method.to_s =~ /^map_([_a-zA-Z]\w*)_to_([_a-zA-Z]\w*)$/
      self.dynamic_mapper_key   = $1
      self.dynamic_mapper_value = $2
    end
  end

  def map_dynamically(method)
    inject({}) do |result, hash|
      result.update(hash[dynamic_mapper_key] => hash[dynamic_mapper_value])
    end
  end
end

puts project_hashes.map_name_to_color.inspect

# {"suspenders"=>"red", "shoulda"=>"green", "high_voltage"=>"green", "gemcutter"=>"green",
# "paperclip"=>"green", "factory_girl"=>"green", "umbrellatoday"=>"green", "hoptoad"=>"green"}

Really nice... I recently read about it in the Metaprogramming Ruby book.

Instead of openening array, I would maybe just decorate each array with a module that includes the dynamic stuff. Then you aren't messing with core libs and it only adds the functionality to the specific arrays that need it.