put a " I *hart* michael jackson" fan sticker on your car
i am/been in a similar situation, the kids of the house behind me (so their backyard begins where mine ends) are totally out of their mind ... there's only 2 of them but they make enough noise for 10
I don't mind kids playing and having fun, but fuck, i have my rights to a quiet afternoon/evening aswell.
Luckily they're moving out shortly, they sold their house
It's tricky, certainly because you're new and you don't really want everybody to look at you as the "bad guy who doesn't allow their kids to play"
Hoping that those parents have half a brain and would tell their kids act normal is one thing you can tho, but it's not very likely these days.
You'll be glad when it's raining ;)