Rated 5 out of 5 stars

Always loved greasemonkey. The best thing since sliced monkey. Seems to not be showing the install dialog in Firefox 29 though -- but I'm sure this will get fixed soon.

PS. Try http://monkeyguts.com for a decent replacement script site, though it's brand new and doesn't have a user base yet.

This review is for a previous version of the add-on (1.15.1-signed).