Django is a python based web-framework. It can be found at http://www.djangoproject.com/.
In Django, first you define your database models as Python classes, to allow Django to understand the data and generate SQL for the database. This is essential for the DRY concept. Next, the views are written; this is where any business logic, interactions with the database and the like go. Then, regular expressions are defined to map requested URLs to the views previously written. Finally, templates are written, which are HTML(or anything composed of text) with data and simple data control sprinkled throughout.
Also see http://docs.djangoproject.com/
Django on Ubuntu
In Ubuntu the package is called python-django