Below you can find competition information and study materials to help you prepare for academic competition:
JCPS Mayor's Cup Information and Dates
The Kentucky Association for Academic Competition
These are a great study resource for all Quick Recall students, from beginners to advanced students. Unfortunately, there's not an Arts & Humanities book. There are two Social Studies books; the other (not pictured below) is focused on world history, which isn't as relevant at the Elementary level but is a great resource for Middle Grades students. Clicking a picture will take you to the Amazon page for each book, and they can also be found at retail book stores like Barnes & Noble and Target (I've even seen them at the school book fair a few times).
They've release some newer books (Computer Science, Pre-Algebra, Geometry, Biology, and Chemistry). For purposes of Elementary Quick Recall/Quiz Bowl, the Computer Science book isn't going to be useful (though it's still very informative in it's own right). Both sets of new Math and Science books are useful. For Math, I would recommend completing them in this order: Math -> Geometry -> Pre-Algebra. For Science, I would recommend Science -> Biology -> Chemistry.