The "Stolen Pace-Egg" Case

In the late 1890s, a frantic man actually sent a letter to 221B Baker Street (which didn't exist as a real address at the time, so the post office forwarded it to Conan Doyle). The man begged Sherlock Holmes to investigate the "theft of a valuable pace-egg" (a traditional dyed Easter egg) from his kitchen. Conan Doyle was so amused and bewildered by the insignificance of the "crime" that he framed the letter and hung it in his study.