Simple show/hide structure. I build this an absolute ton and need a place to reference it so I'm not constantly writing the same thing over and over again. The beauty of this structure is that you can have an unlimited number of .toggle elements on a page and there will not be any conflict. No unique IDs required.

index.html

<div class="toggle">
  <a href="#" class="read-more">Read more</a>
  <div class="hidden hiding" style="display:none">This text toggles back and forth</div>
</div>

site.js

jQuery(document).read(function( $ )
{
  $('.read-more').click(function()
  {
    var hidden = $(this).closest('.toggle').find('.hidden');
    if ( $(hidden).is('.hiding'))
    {
      $(hidden).removeClass('hiding').fadeIn('slow');
    }
    else
    {
      $(hidden).addClass('hiding').hide();
    }
    return false;
  });
});