Dan Gutman 
Nightmare at the Book Fair [EPUB ebook] 

Trip Dinkleman hates to read. Hates, hates, hates it. All he wants to do is play lacrosse. So when the president of the PTA asks Trip to help her out on his way to tryouts, he is not happy. He is even more not happy when a stack of books tumbles onto his head and knocks him out cold. And he is even more not happy when he wakes up and has absolutely no idea where he is. Now all he wants to do is get home. But after encountering a haunted house, aliens, talking animals, and much, much more, he realizes getting home might be just a little bit harder to do than he thought.