Au Revoir, Crazy European Chick by Joe Schrieber is everything you're looking for in a book. Humor... hijinks... hopeless romanticism? (Yeah, the third seems out of place in that alliterated list, but it fits in the book.)
Joe Schreiber, who's past is mostly genre writing, has stretched himself into the thriller (YA) category and come up with a story that's entirely implausible and non-stop fun. He's developed characters that are totally believable and represent the kind of people that you would want to be best friends with. (As an aside, I didn't know there were so many ways to describe minuscule shifts in the gastrointestinal tract that illustrated nervousness until having read this book.)
I'd recommend this book for fans of slick spy movies that involve lots of hand-to-hand combat (think Mr. & Mrs. Smith) because his writing is so well told that it reads like watching a movie.
I'd also recommend that everyone read this book and then expectantly wait for next fall when the sequel comes out.