I recommend The Encyclopedia of Immaturity extremely highly, even though I've never read it. In fact, it's because I've never read it that I recommend it.
Here's why - the book tells you not to let your parents read it. And my son has never let me. A book that a kid keeps to himself that vigorously is a book that a kid loves.
I do know what's in it, though. How? Because my son buries his face in it and then comes downstairs and plays a funny prank on us, or tells us a ridiculous joke, or does something crazy and boyish that he's learned from the book.
Here's what the book has taught him: how to make fart noises using his armpit; how skip stones; how to ride a unicycle (hasn't quite mastered that yet); yo-yo tricks; how to fake a sneeze and about a million other things.
Think your son will read this book? He will. And then he'll act like a complete goofball ever after. Which is how it should be.
If number one on my list of "your-boy-will-read-this" books is The Guinness Book of World Records, this book is number two. And if you're the kind of kid that would read this book, you'll snort with laughter because I just said "number two."