pythonでmarkdownを扱う ref: http://qiita.com/pistatium@github/items/982c6fc0b3c7cf226799

md_test.py

import markdown

md = markdown.Markdown()

sample_makedown = '''
An h1 header
============

Paragraphs are separated by a blank line.

2nd paragraph. *Italic*, **bold**, `monospace`. Itemized lists
look like:

  * this one
  * that one
  * the other one
'''

# makedown -> html
print md.convert(sample_makedown)

myfilter.py

import markdown
#キャッシュするためここで宣言、初期化しとく
md = markdown.Markdown()

@register.filter
@stringfilter
def mark2html(value):
    return md.convert(value)

template.html

{% load myfilter %}

{{ markdown_text|mark2html }}

出力結果

<h1>An h1 header</h1>
<p>Paragraphs are separated by a blank line.</p>
<p>2nd paragraph. <em>Italic</em>, <strong>bold</strong>, <code>monospace</code>. Itemized lists
look like:</p>
<ul>
<li>this one</li>
<li>that one</li>
<li>the other one</li>
</ul>