The vastness of jQuery always surprises me. It is actually not so vast itself, but the fact that it can be flexibly employed to a vast number of client side web applications, intricate or lucid, and adapting well to the environment makes it an essential part of any production site.
Greensock, on the other hand, is a recently developed platform working on JavaScript (for HTML5 applications) and ActionScript (for Flash applications) which makes writing complex animation sequences extremely easy. As it proudly claims, it can “tween ANY numeric property of ANY JavaScript object” [1]. It actually has no dependency on jQuery, but only needs a selector engine like Sizzle (which is actually the selector engine of jQuery) to select elements for animation methods.
Both these powerful platforms are efficiently and very creatively combined in a jQuery Plugin called Scroll Magic. It is actually so light and efficient, and not to mention extremely awesome, that even Google tried it out. It has already over 2600 watchers and over 330 forks on GitHub[2]. In fact, it is more dependent on GSAP than jQuery (in a manner of speaking) as the scroll scenes can be wrapped up in about 12-15 lines of code at the maximum for a good production site. This actually further proves that GSAP is extremely powerful and there is nothing else which can deliver the level of functionality without writing pages of code.
I was very much impressed by the plugin which further inspired me to try out GSAP and create some mind-blowing animations purely written by it. I will be very soon taking it up and would shortly release a walkthrough of the same.