I have followed XKCD for years. His What If? blog (and book) is really good as well. He walks step-by step through the inputs and effects of the questions. The What If for the video below is Relativistic Baseball. If the video does not load, then try Randall Munroe: Comics That Ask What If?
I posted “My Top 10 Life Changing Books” back in September. Such a list is terribly hard for me, so here is another one focused on a dear to me genre.