Oh sorry I missed all the questions/replies for this.
I have my own firefox extension which I hacked up from an abandoned old firefox extension (called "soundextension" by Torisugari) not suitable for release, but there is a more modern extension here which does most of the same:
I vaguely remember I also had to edit the sound files to cut the volume way down, so my PC sound could be at normal levels while the clicks were much more subtle in the background.
Once your brain is trained as to which click means what, you get a good sense of what a page is doing, sneakily or otherwise. Won't work with websockets though.
