The Sword of Good by Eliezer Yudkowsky

Here's a book that makes you laugh and think at the same time.  The hero of the story is named Hirou.  If you don't get it, try saying it out loud.  He's been transported from modern-day Earth to a fantasy realm that he turns out to be the prince of.  Hirou's weapon of choice is the bluntly named Sword of Good that destroys its owner if the owner doesn't have good intentions.  There's a prophecy involved that he will face the Lord of Dark and be given a choice between Good and Bad.  Of course, Hirou instantly tells his friends that he'll choose good: the options being named "good" and "bad" are kind of a giveaway for him, as well as the bad guy being called the "Lord of Dark" and numerous other blatant wordings.  It turns out at the end that it's a tad more complicated than that, but I'll let you read it and see what happens.  It's an online book, and you can read it here: http://yudkowsky.net/other/fiction/the-sword-of-good

Up almost until the very end, it delivers wonderful humor.  The last part transitions into high drama that will keep you turning the -- scrolling your mouse until the last sentence is done.  The Sword of Good deconstructs the typical aspects of a fantasy story.  Hirou is able to question the normal fantasy conventions because he comes from our world.  If you were told you'd be given a choice between good and bad and then asked which one you'd pick in the future, you'd say good without hesitation too.  The other characters are all surprised when he does this, too, for added laughs.

The only real flaw I noticed was that it mentions the TV tropes wiki.  I love TV tropes.  I spend hours at a time on it when I'm supposed to be doing schoolwork.  I know almost all of the regular terminology, and I love reading about TV tropes... on TV tropes.  When somebody references a term from TV tropes outside of the website, it never comes off well.  Mentioning the website itself sounds even worse, staining the next few paragraphs with a bad feeling of pretentiousness. 

Except for the single sentence about TV tropes, however, the book was enjoyable, thought-provoking, and amusing throughout.  If you're stuck somewhere with only your laptop and need a good book, The Sword of Good would be an excellent choice.