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.
It depends largely on the effort you want to expend on this, but the basic outline of an easy way. Would be to load an image of an arrow, and use a drawing library to color and rotate it in the direction you want to point(or draw it using shapes/curves).
Finally to actually animate it interpolate between the coordinates based on time.
If its just for a presentation though, I would use Macromedia Flash, or a similar animation program.(would do the same as above but you don't need to program anything)
How to create a picture with animated aspects programmatically