If you want a medical related book, but one to RELAX by, I reccomend Emergency, I think by Mark Brown, (but I am not sure about the author.) The book has true stories of people who go to the emergency room. I laughed to tears reading some of them.
If you want a non related book, here are some of my favorites.
Funny
John Irving , "A World According to Garp," or "A prayer for Owen Meany"
Irving is a good writer. His books are odd, with lots of strange, interesting characters and sexual humor.
Irvine Welsh, "Trainspotting," "Filth."
Maybe you can't handle Welsh. Lots of people can't. He writes phonetically in Scottish ghetto talk. His books are about drugs, sex, and other unpleasant things. Really funny.
Serious but funny, religion, the meaning of life
Kurt Vonnegut, "The sirens of Titan"
This books best part is his explanation that if their is a higher power, he cares absolutely nothing about the luck of individuals. He didn't make you do good on your MCAT because he loves you, and he didn't make me break my arm in March because he hates me.
Action
Shane Scully "Hollywood tough"
You won't have to use your brain a bit, but it will entertain you. The guy who wrote it made TV shows for a while.