Recommended in /req/, this little Greasemonkey script will add a collapsible navigation menu on every board and thread page. This is intended for people who don't like to use the frame for navigation.
Distributed on a "works for me" basis. I only know enough Javascript to do small hacks like this so I won't add other features myself. Use this thread to report issues or success.

• Greasemonkey script URL: http://userscripts.org/scripts/show/28128
• Screenshot: http://img363.imageshack.us/img363/7653/screenhf9.png
• Greasemonkey Firefox Extension (required): http://www.greasespot.net/
• Original /req/ thread: http://4-ch.net/req/kareha.pl/1212565492/

>>2
Changing the line

var css  = '#greasemonkeymenu { position: absolute; z-index: 9001; right:0px;}' + 

to

var css  = '#greasemonkeymenu { position: fixed; z-index: 9001; right:0px;}' + 

will do the trick

Forgot to mention, to edit the script:
Tools > Greasemonkey > Choose the script > Edit