I love reading middle grade books. These books are full of whimsy and adventure and tend to focus on simple pleasures. They make for great comfort reads. If you think you are too old for a good middle grade novel then you are missing out on some of the greatest books that are out there.
Just to make sure we are all on the same page, let's define what qualifies as 'middle grade'. Technically it is books written for ages 8-12. Basically, it's anything I would call a chapter book. They mainly tend to focus on family and friendship and the internal development of the protagonist.
It is not the same as young adult.
The series I always recommend giving kids when they are first confident enough to read on their own is The Boxcar Children by Gertrude Chandler Warner. I cannot tell you how many times I read these books as a kid (and sometimes still do). These books follow the adventures four orphaned siblings through many adventures. There is always a mystery to solve and someone that they help along the way. These are great easy reads for beginning readers. One little note: there are well over 100 books in this series now. I only recommend the first 19. After that they are authored by someone else and not nearly as good. If you have already read this series and would like something along the same lines, try The Mysterious Benedict Society by Trenton Lee Stewart. More stories of intelligent, creative, caring children.
No list of middle grade books would be complete without mentioning Roald Dahl. His books are creative and funny and sometimes bizarre, but always worth reading. I recommend starting with either Matilda, James and the Giant Peach, or The BFG.
Another author worth mentioning is Kate DiCamillo who wrote Because of Winn-Dixie, The Tale of Despereaux, The Miraculous Journey of Edward Tulane, and Flora and Ulysses. Check out her books especially if you have a child who loves animals.
And while we're on the subject of animals: Mrs. Frisby and the Rats of NIHM by Robert C. O'Brien. I have only read this book in the last year and I am so sorry I missed out on it as a child. This is the book that the movie The Secret of NIMH is based off of and it is so so good.
(Side note: Both Mrs. Frisby and the Rats of NIMH and Flora and Ulysses will be under my own Christmas tree this year as gifts for nieces. Shhhh don't tell...)
We are just going to hit on one more category today and that is family sagas. I love books that follow a single family. There aren't necessarily huge adventures or dramatic endings. They are just simple stories of families living life together, siblings fighting and learning to love each other. They are feel good stories. I especially love The Melendy Quartet by Elizabeth Enright (be sure to start with The Saturdays) and The Penderwicks by Jeanne Birdsall.
I hope this gave you a few new ideas. This is just scratching the surface, there are so many great middle grade books out there!