Tampermonkey can be installed from here: http://tampermonkey.net
Once installed, click on the link below to install the script:
Click to install (v2.4.0+5653a3c57598481f8355366ea18c32ece89a898c)
Current features include:
Bookmarklets are small scripts you can run by clicking a link in your bookmark bar.
To 'install' a bookmarklet, drag the link into your bookmarks bar.