XKCD What If? Book
You might have stumbled on XKCD’s What If? in which XKCD creator Randall Munroe answers fun hypothetical questions, such as What if I took a swim in a spent-nuclear-fuel pool? and Could you build a jetpack using downward-firing machine guns?. He bundled his favorite and a couple of new questions in a book.
I have already bought the book and I have to say it is a good read. He also responds with a comic to questions that were too weird for him. It is also a nice way to support the XKCD web comic.