I recently read a book this summer that reminded me of the Whimpy Kid crowd. It's called "Swim the Fly".
The description for "Swim the Fly" reads as follows:
"Fifteen-year-old Matt Gratton and his two best friends, Coop and Sean, always set themselves a summertime goal. This year's? To see a real-live naked girl for the first time — quite a challenge, given that none of the guys has the nerve to even ask a girl out on a date. But catching a girl in the buff starts to look easy compared to Matt's other summertime aspiration: to swim the 100-yard butterfly (the hardest stroke known to God or man) as a way to impress Kelly West, the sizzling new star of the swim team. In the spirit of Hollywood’s blockbuster comedies, screenwriter-turned-YA-novelist Don Calame unleashes a true ode to the adolescent male: characters who are side-splittingly funny, sometimes crude, yet always full of heart."
I'm not sure if it's considered a Young Adult book, but I wouldn't recommend it for children under the age of about 14. The boys in the book are 15, after all, and talk like 15 year old boys. Plus, their goal for the summer is to see a live naked girl. Maybe not appropriate for your 12 year old to read.
Anyway, I found the book to be hilarious and laughed out loud several times. It's a quick read at about 350 pages. I read it on my Kindle Fire, so I got it for the low price of $2.99!
I'm reading the follow up now. It's called "Beat the Band". It's another enjoyable adventure with the boys. I'll let you know how I liked it when I'm done.
If you're looking for a quick summer read, "Swim the Fly" is a great one!