Global Animations

Okay, so while I know quite a bit about Age creation, enough to write tutorials, I don't know everything of course.
The main way I DID learn so much was by asking you guys here question after question, after question, after....well those of you that have been where a while know that 3 years ago I was a major thorn in your side.
So I'm back with a new thorn: Global Animations.
I want to know how they are done. Not the PyPRP part. I simply want to know how Gira has a day and night cycle.
What is going on? How did Cyan do this? What is a good way? What is a wrong way? What is a "so bad it will screw everything up" way?
How would you do it? Lay it on me.
The main way I DID learn so much was by asking you guys here question after question, after question, after....well those of you that have been where a while know that 3 years ago I was a major thorn in your side.
So I'm back with a new thorn: Global Animations.
I want to know how they are done. Not the PyPRP part. I simply want to know how Gira has a day and night cycle.
What is going on? How did Cyan do this? What is a good way? What is a wrong way? What is a "so bad it will screw everything up" way?
How would you do it? Lay it on me.
