I took 25 foot of 4 foot high fence and made a circle, about 8 feet across and started filling it up. It took about 8 hours over 3 days to fill it up. I got most of the easy leaves raked but there are still a lot of leaves embedded in clover. Maybe when I mow, I'll catch the grass (mostly clover) and dump it in the new ball pit.
I call this our Redneck Ball Pit but I could probably call it a Hippy Ball Pit (right J-mac?)
Here are a couple of pictures of Kimberly and the pit: