My daughter loves the Junie B Jones series chapter books; I know you've got boys, but Junie isn't too girly at all! She's hilarious, infact, and my husband and I both enjoy reading the books and even laugh about them afterwards.
We've also just begun Roald Dahl's books, which my husband loved as a boy. We just finished George's Marvelous Medicine, which was a riot.
I'd suggest going to Borders and checking out the early reader's chapter books section (can't remember exactly what the title of the section is, but an employee can point you in the right direction). Along with Junie B Jones you'll find tons of other titles/series that would be great for your guys!