import re
text ='''
<p><script type="text/javascript"> if (window.showTocToggle) { var tocShowText = "show"; var tocHideText = "hide"; showTocToggle(); } </script>
</p><p><br />
</p>
<div class="editsection" style="float:right;margin-left:5px;">[<a href="/w/Template:Method/edit?section=4" title="Template:Method">edit</a>]</div><a name="Description"></a><h3>Description</h3>
<p>Inserts a command to the server queue at the beginning and forces execution.
</p>
<div class="editsection" style="float:right;margin-left:5px;">[<a href="/w/Template:Method/edit?section=5" title="Template:Method">edit</a>]</div><a name="Arguments"></a><h3>Arguments</h3>
<p><br />
</p>
'''

print re.findall(r"Description</h3>(.*?)</p>", text)

re.search('Inserts a command to the server queue at the beginning and forces execution.', text)

print re.findall(r"Description</h3>\s*<p[^>]*>(.*?)</p>", text, re.S | re.I)

print re.findall(r"Description</h3>\n<p>(.*?)</p>", text, re.DOTALL)

print re.findall(r"Description</h3>\s+<p>(.*?)</p>", text, re.DOTALL)