<table>
<thead>
<tr>
<th></th>
<th></th>
<th></th>
<th></th>
</tr>
</thead>
<tbody>
<tr>
<td></td>
<td></td>
<td></td>
<td></td>
</tr>
<tr>
<td></td>
<td></td>
<td></td>
<td></td>
</tr>
<tr>
<td></td>
<td></td>
<td></td>
<td></td>
</tr>
</tbody>
</table>
Valid technique, as it doesn't need the <embed> tag.
<object type="video/x-ms-wmv"
data="movie.wmv"
width="320" height="260">
<param name="src"
value="movie.wmv" />
<param name="autostart" value="true" />
<param name="controller" value="true" />
</object>
Quicktime still requires the double-object method to get it done across all browsers. Not super pretty, but it does get the job done.
<object classid="clsid:02BF25D5-8C17-4B23-BC80-D3488ABDDC6B"
codebase="http://www.apple.com/qtactivex/qtplugin.cab"
width="200" height="16">
<param name="src" value="movie.mov" />
<param name="autoplay" value="true" />
<param name="pluginspage" value="http://www.apple.com/quicktime/download/" />
<param name="controller" value="true" />
<!--[if !IE]> <-->
<object data="movie.mov" width="200" height="16" type="video/quicktime">
<param name="pluginurl" value="http://www.apple.com/quicktime/download/" />
<param name="controller" value="true" />
</object>
<!--> <![endif]-->
</object>
This is different than the default code that Flash provides. That typically involves the <embed> tag and is not valid XHTML. This doesn't use that, and is fully valid.
<object type="application/x-shockwave-flash"
data="your-flash-file.swf"
width="0" height="0">
<param name="movie" value="your-flash-file.swf" />
<param name="quality" value="high"/>
</object>
<div id="header">
<p>Stuff</p>
</div> <!-- END div-header -->The <!-- --> stuff is the HTML comment. It is a way to add notes into the code which will not display when the HTML is rendered by the browser. In the example above, to signify which opening div tag the closing tag was actually closing.
You can use carriage return characters to break the line: 

<input type="button" value="Really
Tall
 Button">
A basic address and URL, marked up using Microformats.
<div id="hcard-Christopher-John-Coyier" class="vcard">
<a class="url fn n" href="http://chriscoyier.net">
<span class="given-name">Christopher</span>
<span class="additional-name">John</span>
<span class="family-name">Coyier</span>
</a>
<div class="org">CSS-Tricks</div>
<a class="email" href="mailto:chriscoyier@gmail.com">chriscoyier@gmail.com</a>
<div class="adr">
<div class="street-address">123 Appleseed Street</div>
<span class="locality">Chicago</span>, <span class="region">IL </span> <span class="postal-code">60647</span>
<span class="country-name">United States</span>
</div>
<div class="tel">555-555-5555</div>
</div>