This is just some animation I whipped up in my spare time for a contest. It is two bouncing balls. One is a basket ball, the other is a beach ball. I tried to capture the difference in weight and volume. The basketball definitely needs some work in that department, but I felt the beach ball is pretty reasonable.
The dirt was just something I added to give the effect of friction and life to the ground.
The beach ball isn't very round I know, but I did this in a rush, and as a test. All things considered, I could have just used motion tweening and this probably would've been done faster... oh well.