Hi there. Taking my own advice, I’ve gotten a little back into coding and greatly revised the bouncing ball/gravity simulation I did with Flash a while ago. It’s still in the menu to the left as “actionscript bouncing ball” except now there are two balls, they are coloured, you can throw them around yourself by dragging and releasing, they don’t sink through the bottom any more, you can control the gravity, and the bouncing is cleaner.
Anyway, thought you might like to play. Very small, quick to load, Flash 6+.