In no particular order.....
Out of My Mind by Sharon Draper
The Candymakers by Wendy Mass
Oggie Cooder by Sarah Weeks
When You Reach Me by Rebecca Stead
The Lightning Thief by Rick Riordan
The Penderwicks by Jeanne Birdsall
The Wright 3 by Blue Bailliet
The Golden Hour by Maiya Williams
Ida B (and her plans to maximize fun...) by Katharine Hannigan
The Miraculous Journey of Edward Tulane by Kate DiCamillo
Each Little Bird that Sings by Deborah Wiles
The City of Ember by Jeanne DuPrau
Chicken Boy by Frances O'Roark Dowell
The Giants and the Joneses by Julia Donaldson
The Anybodies by N. E. Bode
Penny From Heaven by Jennifer L. Holm
The Mysterious Benedict Society by Trenton Lee Stewart
Running Out of Time by Margaret Peterson Haddix
...and some classics:
From the Mixed-up Files of Mrs. Basil E. Frankweiler by E. L. Konigsburg
A Wrinkle in Time by Madeleine L'Engle
The Westing Game by Ellen Raskin
Any book by Edward Eager