Sometime around junior high, this Weizmann science writer stumbled upon Mathematical Games, the late Martin Gardner's monthly math puzzle at the back of my mom's Scientific American, and I became a devotee. The best ones, of course, were those that required a little sideways thinking, and these yielded the pleasure of that "Aha" moment when the answer became clear. (For more on the neurobiology of the Aha moment, look at our site.)