"Kids"
Why complicate things? I just searched and didn't see that name in the first 50 results yet I imagine the word is searched for thousands of times a day.
On paper, your suggestion is so common sensical, practical, perfect. But two ideas pop to mind.
1- Maybe "Kids" has been taken already, by a developer who might still be working on it? I don't know what the App naming rules are like.
2- You think that Rolando would've sold as much if it had been called, Rolling Balls? Sometimes you have to jazz it up a bit.
I love this thread, BTW.