I had to abort the full render after 8hrs or so, as I was a bit ambitious with the settings. Here is the Open GL version of the challenge. Fortunately, I rendered in png files as we were taught earlier. It may be possible to complete the render another time.
The idea is to simulate three kinds of balls; a bowling ball, a tennis ball and a golf ball. The graph editor and the dope sheet were really useful to tweak the animation. This was a good exercise to do. Just need to practice it a bit now.