1994
The cover of EGM had what was claimed to be an intentional typo: "Streeets of Rage 3". The reality of the situation, however, was that everyone on the magazine's staff had forgotten that they were working on the April issue, and no actual joke was created. After the issue had been produced, the staff realized its oversight, causing them to scramble to find an excuse for forgetting their tradition. "Luckily", there happened to be a typo on the issue's cover, which was quickly adopted as the April Fool's joke. EGM finally admitted to this fake April Fools' joke ten years later on page 57 of the May 2004 issue (#178).
At the time, no one writing in correctly guessed this to be the joke. However, many readers wrote in guessing, incorrectly, that a code for Mega Man X, giving X a Street Fighter-style Hadouken, was fake.
Read more about this topic: EGM April Fools' Jokes