I Love Papervision.

Papervision is a set of ActionScript classes dealing with 3D rendering. Not having any prior experience in 3D or any other tools - Maya, etc - that is really as much detail as I can describe it with.

But basically, it will take your 2D ActionScript stage with an x and a y axis and add an additional z axis:

(image credit devshed.com)

This has fantastic implications for all kinds of super cool and neat display capabilities, in addition to allowing for the development of an interactive 3D space. I've been working through it thanks to the fantastic publication Papervision3D Essentials and I have to say it's super cool. Expect more from this front soon.