I know what you want. I see you. You come in to the library with that little-bit-panicked look in your eye: "Oh shit there's no school for like MONTHS and they're going to do nothing but play Minecraft and moan about being bored." Or pull scary crap like balance-beam on an 8-foot fence. YEESH.
I am right there with you. Milo is in the basement right this second watching those awful Sky Does Minecraft YouTube videos. Or porn. No I did not just write that. I take it back. Wait, let me just get him up here, I'll be right back.
He was practicing guitar. OF COURSE. God, I am so not ready for him to be a teen.
Anyway, you want book recommendations for your children so that they do not forget how to read / become glassy-eyed screen zombies over the summer. You want books that are IRRESISTABLE, books that they will plough through and then ask for the next. In short, you want series books, and you want series that have been out for long enough that there's no waiting for the next book.