Markdown is a text-to-HTML filter; it translates an easy-to-read /
easy-to-write structured text format into HTML.  Markdown's text
format is most similar to that of plain text email, and supports
features such as headers, *emphasis*, code blocks, blockquotes, and
links.  -- http://daringfireball.net/projects/markdown/

This is a fast and complete Python implementation of the Markdown
spec.