/*- Маска -*/
#mask {
  position:absolute;
  left:0;
  top:0;
  width:100%!important;
  height:100%!important;
  z-index:9000;
  background:#000 url(http://webelement.info/materials/WebModal/bg.png);
  display:none;
}

/*- Общие стили окошка -*/
#box .window {
  position:absolute;
  left:0;
  top:0;
  max-width:560px;
  max-height:90%;
  display:none;
  z-index:9999;
  padding:0px;
-moz-box-shadow: 0px 0px 25px #000000;
-webkit-box-shadow: 0px 0px 25px #000000;
box-shadow: 0px 0px 25px #000000;
}

/*- Верхняя часть окошка -*/
.window .window_header {
display:block;
position:absolute;
left:0;
top:-10px;
width:560px;
font-size:16px;
font-weight: bold;
color:#444;
background:#eee;
padding:0px;
}

/*- Отступы контента -*/
#window_content{
  padding:40px 20px 20px 20px;
}

/*- Отступы для title окошка -*/
.window_title{
padding:10px 10px 10px 20px;
}

/*- Стиль для первого окошка -*/
#box #dialog {
  width:100%;
  height:auto;
  background-color:#ffffff;
}

/*- Стиль для второго окошка -*/
#box #dialog2 {
  width:100%;
  height:auto;
  background-color:#ffffff;
}

/*- Стиль для видео -*/
#box #video {
  width:100%;
  height:auto;
  background-color:#ffffff;
}
/*- Убираем отступы для видео -*/
#box #video #window_content{
padding:0px;
}

/*- Ссылка на закрытие окна -*/
.close{
font-weight:normal;
display:inline-block;
position:absolute;
top:10px;
right:10px;
}
/*- Размеры для видео: width:560; height:315; -*/

<script type="text/javascript">
$(document).ready(function() {
  $('a[name=modal]').click(function(e) {
  e.preventDefault();
  var id = $(this).attr('href');
  var maskHeight = $(document).height();
  var maskWidth = $(window).width();
  $('#mask').css({'width':maskWidth,'height':maskHeight});
  $('#mask').fadeIn(300);
  $('#mask').fadeTo("slow",0.7);
  var winH = $(window).height();
  var winW = $(window).width();
  $(id).css('top', winH/2-$(id).height()/2);
  $(id).css('left', winW/2-$(id).width()/2);
  $(id).fadeIn(300);
  });
  $('.window .close').click(function (e) {
  e.preventDefault();
  $('#mask, .window').hide();
  });
  $('#mask').click(function () {
  $(this).hide();
  $('.window').hide();
  });
});
</script>

<!-- Внутри этого дива должны быть ваши окна -->
<div id="box">

<!-- Много контента -->
<div id="dialog" class="window">
<div class="window_header">
<div class="window_title">Модальное окно<a href="#"class="close"/>Закрыть</a></div>
</div>
<div id="window_content">
Lorem Ipsum is simply dummy text of the printing and typesetting industry. Lorem Ipsum has been the industry's standard dummy text ever since the 1500s, when an unknown printer took a galley of type and scrambled it to make a type specimen book. It has survived not only five centuries, but also the leap into electronic typesetting, remaining essentially unchanged. It was popularised in the 1960s with the release of Letraset sheets containing Lorem Ipsum passages, and more recently with desktop publishing software like Aldus PageMaker including versions of Lorem Ipsum.
Lorem Ipsum is simply dummy text of the printing and typesetting industry. Lorem Ipsum has been the industry's standard dummy text ever since the 1500s, when an unknown printer took a galley of type and scrambled it to make a type specimen book. It has survived not only five centuries, but also the leap into electronic typesetting, remaining essentially unchanged. It was popularised in the 1960s with the release of Letraset sheets containing Lorem Ipsum passages, and more recently with desktop publishing software like Aldus PageMaker including versions of Lorem Ipsum.
</div>
</div>
<!-- Меньше контента-->
<div id="dialog2" class="window">
<div class="window_header">
<div class="window_title">Модальное окно 1<a href="#"class="close"/>Закрыть</a></div>
</div>
<div id="window_content">
Lorem Ipsum is simply dumet sheets containing Lorem Ipsum passages, and more recently with desktop publishing software like Aldus PageMaker including versions of Lorem Ipsum.
</div>
</div>
<!-- Вариант с видео-->
<div id="video" class="window">
<div class="window_header">
<div class="window_title">Video<a href="#"class="close"/>Закрыть</a></div>
</div>
<div id="window_content">
<iframe width="560" height="315" src="http://www.youtube.com/embed/ID видео" frameborder="0" allowfullscreen></iframe>
</div>
</div>
<!-- Маска (Обязательно в конце всех окошек)-->
<div id="mask"></div>
</div>

<a href="#dialog" class="link" name="modal">Модальное окно</a>
<a href="#dialog2" class="link" name="modal">Модальное окно 1</a>
<a href="#video" class="link" name="modal">Video</a>