helper.rb

def button_tag_menu(value, options={}, &block)
  options[:onclick] = "$(this).up('.menuButton').down('.menu').show();"
  %{
    <div class="menuButton">
      #{button_tag(value, options)}
      <div class="menu" style="display: none;">
        #{capture(&block)}
      </div>
    </div>
  }
end