I stumbled across this post using the ASP.NET Ajax AnimationExtender to move points around and immediately recognised the similarities to the Silverlight 'race simulator' demos I've been playing with.
It seemed a natural progression to try animating same North Head (Sydney) race runner data using ASP.NET AJAX to animate the runner markers. A quick massage of the Silverlight XAML (using Excel!) and I had a couple of JSON arrays ready to go.
The result, as you can see, is not quite as smooth as Silverlight - and I suspect that Ajax would have even more trouble than Silverlight with 400 elements to animate!
View Sourceof the AJAX page - it's all there.
I took at look at the racing example and it looks COOL!!!.
In my example I use JSON elements in an array to hold points in the path, for small samples , this is cool.
For huge number of points, you might consider going with a two-dimensional array of points , or 2 single dimensional arrays ,to remove the cost of 'eval'ing points in the array .
but , all said , the app looks pretty cool.
Great job !!