By dynamic menus, I assume you mean you want a navbar or something in the layout to change based on the context of a user's session. So, you may have different tools associated with each page, right?
Assuming we're on the right track, I'd explore using the flash system for something like that. So, you could set your flash[:navbar] to something in your application controller, and then override it where you would like to have it work differently in other controllers.
Also, I found this helpful in Scott Raymond's Ajax on Rails book. He puts a simple method in his application_helper.rb:
def flash_div *keys divs = keys.select { |k| flash[k] }.collect do |k| content_tag :div, flash[k], :class => "flash #{k}" end divs.join end
Cheers,
