29 October 2012 - It looks like Wikipedia has done away with the ability to toggle the TOC open and closed so this style doesn't work any more. I'm going to leave it "active" just in case.

Wikipedia pages will open with the Table of Contents minimized. The toggle link initially says "hide", as if it's maximized, but it's just temporarily hidden. Click twice to open the TOC the first time. After that it behaves normally.

This may have been done before but there are too many Wikipedia hacks to look through to tell. I apologize if I have stolen anyone's idea.

Change or add domains as desired. I have tested it only on the domain in the code but it should work on many others.

Important! Do NOT add "!important" to the end of this code or the TOC will be permanently hidden.