how to disable facebook ads and applicatons (quizzes etc.)
part 1 - block ads everywhere
• install and use firefox if you don't already
http://www.mozilla.com/en-US/firefox/firefox
• install the adblock-plus extension
https://addons.mozilla.org/en-US/firefox/addon/1865
(or tools → add-ons → get add-ons → search for adblock plus → add)
• restart firefox
• download this list of 8 facebook-filters
• go to menu → tools → add-ons → extensions → adblock plus → preferences
• select filters → import filters
• browse to the facebook-filters.txt file you downloaded, and open it
• click overwrite
part 2 - a facebook ad blocker
• install greasemonkey from https://addons.mozilla.org/firefox/addon/748
• install facebook companion from http://userscripts.org/scripts/show/8475
part 3 - block applications, so you don't get pestered with "what vegetable you most resemble" quizzes etc.
• install auto-block facebook apps from http://userscripts.org/scripts/show/12393
• install facebook purity from http://steeev.freehostia.com/wp/2009/03/19/facebook_purity_cleans_up_the_facebook_homepage This blocks quiz/app stories, there is a link to show them.
• install noquiz from http://userscripts.org/scripts/show/44922 or my modified version facebook-noquiz.user.js. This also blocks quiz/app stories, you can edit it (near line 38) to select what to block.