For MMGM, I am recommending Tuesdays at the Castle by Jessica Day George.
Here's the publisher's description:
See where it all began with Jessica Day George's magical bestselling series!
Tuesdays at Castle Glower are Princess Celie's favorite days. That's because on Tuesdays the castle adds a new room, a turret, or sometimes even an entire wing. No one ever knows what the castle will do next, and no one-other than Celie, that is-takes the time to map out the new additions. But when King and Queen Glower are ambushed and their fate is unknown, it's up to Celie, with her secret knowledge of the castle's never-ending twists and turns, to protect their home and save their kingdom.
I really enjoyed this book! One of my favorite things about it is how original its premise is. The author has taken what seem to be common elements of books, such as magic and royalty, and made a unique mash-up of them, helping to keep the plot interesting and unexpected. Of course, this is helped by the fact that the book moves quickly through many interesting events. Conspiracies are uncovered, people are trapped, and the castle's magic creates many fun twists and turns. Even as the plot rushes forward, however, the characters remain full of life and emotions, never becoming dull or caricatures of themselves. The main character, Celie, is especially likable, never becoming too much like an adult but still rising up in the face of a challenge. Although this book is part of a series, it doesn’t end on a cliffhanger, so you can read it as a standalone book (I felt that the second book in the series went too slowly, but people have enjoyed the later books, so it may be worth it to read the whole series). Whether you read it by itself or along with the rest of the series, Tuesdays at the Castle is a wonderfully fun book for readers of all ages!