Signals and slots is a concept you probably are familiar with if you ever used a framework like QT. It’s especially useful for GUIs.
Andrew Tetlaw has a small writeup about signal and slots in javascript using Alex Russel’s sigslots library - also see signal and slots - an alternative to addEvent
Andrew also wrote a signals and slots implementation for Prototype.
Not a brand new thing, but great things can remain hidden for ages until you discover them by chance.