Background
I have been asked by a client to create a picture of the world which has animated arrows/rays that come from one part of the world to another.   
The rays will be randomized, will represent a transaction, will fade out after they happen and will increase in frequency as time goes on.  The rays will start in one country's boundary and end in another's.  As each animated transaction happens a continuously updating sum of the amounts of all the transactions will be shown at the bottom of the image. The amounts of the individual transactions will be randomized.  There will also be a year showing on the image that will increment every n seconds.
The randomization, summation and incrementing are not a problem for me, but I am at a loss as to how to approach the animation of the arrows/rays.
My question is what is the best way to do this?  What frameworks/libraries are best suited for this job?
I am most fluent in python so python suggestions are most easy for me, but I am open to any elegant way to do this.
The client will present this as a slide in a presentation in a windows machine.
The client will present this as a slide in a presentation in a windows machine

I think this is the key to your answer. Before going to a 3d implementation and writing all the code in the world to create this feature, you need to look at the presentation software.  Chances are, your options will boil down to two things:

Animated Gif
Custom Presentation Scripts

Obviously, an animated gif is not ideal due to the fact that it repeats when it is done rendering, and to make it last a long time would make a large gif.
Custom Presentation Scripts would probably be the other way to allow him to bring it up in a presentation without running any side-programs, or doing anything strange. I'm not sure which presentation application is the target, but this could be valuable information.
He sounds like he's more non-technical and requesting something he doesn't realize will be difficult. I think you should come up with some options, explain the difficulty in implementing them, and suggest another solution that falls into the 'bang for your buck' range.
How to create a picture with animated aspects programmatically