Just stumbled upon this (very long) thread.

So I had to find my red ball - never found it before.

We are directed earlier in the thread to the major clue in the first post: Clue of in the top left corner is the key.

I haven't found it, though I think I've seen it before, when I didn't know what it was. Maybe in the sandbox?

no. its not in the sandbox but it is outside.
im not sure if you want me to tell you or if you want to find it on your own...

here is something i was wondering, and Havetia told me about today... (or maybe she told me yesterday, i forget)

I have not found that to be the case. I have 5 families running, have had the ball in all of them at the same time and sometimes more than 1 ball in the same family at the same time.

cool! I'll keep trying then!

The trick is: when you get it the first time, put it somewhere you can remember (i.e. the sandbox, the kids toys, etc) and then go into your other families and click in the spot where it is in the family you found it in in the first place. It should appear.

Thanks Krystal! It worked!

only found one ball in one family..and that was by accident...havent been able to get it on any of the others

I had the ball for awhile, but it disappeared when I was bouncing it! Here's a couple pics of it and one that is explaining the disappearance better: