I wrote an article the other day stating that I had no idea why someone would call a Helper method from inside a Controller in Rails.
I just found a reason. Here is what I needed to do:

From inside my controller, I wanted to be able to generate some AJAX code that would be sent back to the page. In other words, I needed to generate some HTML (for an AJAX reply) that would be able to make a remote call and the best way to do this is through the link_to_remote() function.
Here is the code I added to my Controller in order to be able to achieve this:

class ConciliationsController < ApplicationController

  # for this example you can use either of the lines below and it should work
  include ActionView::Helpers::PrototypeHelper
  include ActionView::Helpers::JavaScriptHelper

  # this method is called by AJAX, which means that I have also 
  # a cal to link_to_remote in my view
  def reconcile
    @transaction = Transaction.find(params[:transaction_id])

    render :update do |page|
      page.replace_html "transaction-item", 
                                    link_to_remote('reconcile', 
                                         :url => {:action => "reconcile", :transaction_id => @transaction.id} )
    end

  end

end

Cheers!