When it comes to maintaing hundreds of tests this comes in really handy:
python manage.py test --failed
This will only rerun failed tests,
to use it you need to use the nosetests runner and have nose-exclude installed.
See this article for details:
http://webamused.wordpress.com/2010/04/07/tutorial-testing-efficiently-with-nose-nose-exclude-and-django-nose/
