A long-time favorite for me in my classroom has been Hank the Cowdog. There are now over 60 books in this series.
My oldest son got hooked on them in the second grade and is STILL reading them as a sixth grader. My husband is also a big fan (so there really is no age limit on these books). In my second grade classroom, I start reading these aloud while my kiddos are practicing their handwriting. I teach in a rural farming/ranching community and these books grab the attention of my kids like no other book series. The author, John R. Erickson, is a master of capturing ranch life in rural Texas. It helps if they are read aloud with a strong Texas draw ;) By the time that my students are heading to third grade they are dying to get their hands on a “Hank” book for themselves.
The characters in these books are so entertaining and endearing. My sons have literally laughed until they cried retelling me the stories from these books. At home, even my husband will stop to listen if I am reading one aloud with my boys.
A new favorite of mine is the “I Survived” series by Lauren Tarshis. What I love about these books is that it teaches the reader about an historic event through the eyes of a fictional character. I never heard of this series until my middle son (in the third grade) started talking about the Nazi invasion at the dinner table. He had been reading “I Survived Nazi Invasion” and was curious about learning more. He loved all the books in this series and was constantly returning to the school library to see if other ones were available yet.
Lastly, any book by Gary Paulsen is a hit with boys. Honestly, I read some of his books when I was in school and I didn’t think they were too great. However, boys seem to LOVE these books. My oldest is completely fascinated by any of his books. Of course, “Hatchet” is the book that he is best known for. However, he has dozens of books that hold the interest of boys.