Today I've released on Github one of my applications - django-content-bbcode. The parser code is used on my sites and I've decided to refactor it (it's quite old), add some new features (like the tag loader) and release it to the public. There is also pypi package for it.
In short django-content-bbcode allows you to replace BBCode alike tags in text (like in articles, news) with whatever you code in Python. I use it to highlight code snippets (with pygments), make nice links to articles by given slug (fetches title, description from database), insert image thumbnails (integrated with frontend image lightbox) and few more. Makes plain text quite dynamic. More detailed description is on Github.