./app/design/frontend/default/default/template/catalog/navigation/category_list.phtml
<?php
$URL="http://www.panticz.de/sites/default/files/magento/category/category_list.phtml";

echo "<div><pre>";
</pre></div>

$c = curl_init();
curl_setopt($c, CURLOPT_URL, $URL);

echo htmlspecialchars(curl_exec($c));

curl_close($c);

echo "";

?>

cms include php template
{{block type="catalog/navigation" name="catalog.leftnav" template="catalog/navigation/category_list.phtml" cat_id=2227}}

CSS
.category_list ul {
height: 120px;
margin-bottom: 15px;
}

.category_list li {
float: left;
width: 250px;
}