Well known fact: the game Monopoly gives you the chance to pull a Get Out Of Jail Free card. Less well known fact: during WW II, the British spiked games of Monopoly with useful prison break tools and shipped them over to POWs.
During the war, large numbers of British airmen were felled over enemy airspace and then held as prisoners behind enemy lines. Germany, however -- in part as a nod to the Geneva Convention -- allowed humanitarian groups like the Red Cross to distribute care packages to those prisoners. And one of the categories of items that could be included in those packages was "games and pastimes." So the Allies took military advantage of this human kindness: Posing as "charities" (one of the better fake names: the Licensed Victuallers Prisoners Relief Fund), they sent packages to their POWs that featured clandestine escape kits -- kits that included tools like compasses, metal files, money, and, most importantly, maps.
And: They disguised those kits as Monopoly games. The compasses and files? Both disguised as playing pieces. The money, in the form of French, German, and Italian bank notes? Hidden below the Monopoly money. The maps? Concealed within the board itself. "The game was too innocent to raise suspicion," ABC News's Ki Mae Heussner put it -- but "it was the ideal size for a top-secret escape kit."
Urban Legend, you say! Not according to Snopes, which gives the story a 'True' rating (despite some hyperbole in the claims).
As military hacks go, it's a clever one. However, packing POW supplies in games isn't unique to the British. Just down the street, at Fort Hunt, there was a top secret project working on a similar goal. That harmless looking cribbage set, for example, was actually a radio.
Still, there's a nice bit of poetry in packing prison breaking supplies in a game that contained a Get out of Jail card.
Sometimes, the stuff of fiction is just what's called for.