Ender's Game. Plus, bonus - it's going to be a movie in the Fall. Also, the NERDS series. Here's a good flow chart:

http://www.lawrence.lib.ks.us/2012/07/if-you-liked-the-hunger-games-3/

My kids like Carl Hiassen books, Chomp, Flush, Scat, Hoot and there is a new one called Bad Monkey.

Incarceron

How about the Sci-Fi section, my 13 year old has been picking books from that section for at least a year. There are also some appropriate books in the young adult section. For example, my son picked a book from the YA section for a book report recently. I dont remember the name but it was a book about a teenager that lives inside of a video game, or something like that. It was a very thick book.

Honestly, if he's reading books for a younger audience, that's fine too. Enjoying reading is what's important.

Here's a suggest list of books:
http://www.commonsensemedia.org/book-lists/books-boys

check out this site for some good recommendations for books for boys:

http://www.guysread.com/books/lists

There is an older book called "The Mad Scientists Club" that is a really fun and age appropriate read for boys that age. Look it up online.

I have a 12 year old brother who I love to encourage to read. Every time we go to a book store, I tell him I will buy him as many books as he wants as long as he will read them. He usually picks out more "kiddie" books and I know he is way more advanced than that. He recently read the Hunger Games trilogy and seemed to enjoy it, however, he is back to the "easy" books again.

I just don't think he wants to be bothered with a challenging book.

Does anyone have any suggestions for age appropriate books that might encourage him to do more age appropriate reading?