I wrote Quickscript solely for my own use, so I could have a way to run little scripts of my own devising that don't deserve their own extension. Admittedly, it's not very polished (not that any of my extensions are!) or even fully baked. It is, however, at least minimally functional.
(In case you're wondering whether Quickscript supports scripts written for Greasemonkey, it doesn't. Quickscript is a lot simpler and less ambitious than Greasemonkey, and it makes no effort to be compatible with that Firefox extension.)
What is new in this release:
Updated the bundled jQuery to version 2.1.0.