Truman's actual middle name was S (both of his grandfathers had names that began with the letter, so in order to avoid playing favorites by picking a single a name, his parents just went with the initial). However, the practice of putting a period after the S is actually a topic of controversy, and has been known to get editors and punctuation fiends (including us) all riled up. (Source)

Spies, spy rings, and spy culture were a major part of the Cold War for both sides. Hundreds of American agents were caught trying to enter the Soviet Union with fake passports because they had the wrong staples. The staples in U.S.S.R. passports always corroded, while the stainless steel staples used by the Americans did not. Talk about the importance of being detail oriented. (Source)

Legend has it that, during the Cold War, the Soviets always had at least two missiles pointed at a round building located in the center of the Pentagon and visible by spy satellite image. They assumed that this building was the facility's most important meeting room (hence its central location) and that the Pentagon itself was a giant fortress built around this well-guarded, top-security area. Turns out it was just a hot dog stand with a sweet location. (Source)