We're entering into a portion of our project where a bunch of technical artists are creating driven animations for timelapse sequences - it would be nice if they could have simple UIs for the few parameters you can animate. So.... floating sliders seem like a nice hack.
As to what it does, welp, Title sez it all I guess; On selection, you get some floating sliders for any custom properties on Bones (Pose Mode only)
It is quite a hack! and thus could eat some (if not all) babies, especially if you have a really custom keymapping with the left and right mouse buttons.
Read about it:
Watch the video above or on youtube:
And finally, you can get the code from gitorious: