Script Summary: removes quiz stories from homepage; additional filtering possible
To remove all external app (even quizzes) stories, go to: http://userscripts.org/scripts/show/44490
Quiz stories remover for Facebook
Automatically removes quizzes (by default) - stories containg text "quiz and the result is" or "Check out this quiz!"
Script can be extended to remove any stories matching any given string.
Works in interval of 1 sec.
If experiencig any performance difficulties, change interval to 2 sec and more, or disable it completely (see script commentaries).
You need Firefox with Greasemonkey installed in order to run this script.