Flutterby™! : Gravity simulation

Back in college I wrote a bunch of particle simulation stuff that ran on a 4.77 MHz PC XT, working with a professor who was implementing many of the same ideas on 1 MHz 6502 Apple hardware. So when I had 768 massless particles moving at interactive speeds I was pretty pleased with myself, but every time I tried to scale that to gravity simulation... well... that stuff was hard.

So this: This is awesome: http://www.nowykurier.com/toys/gravity/gravity.html