This day in geek history: January 27
1974
First release of Dungeons and Dragons: Dungeons and Dragons (D&D) is a role playing game (RPG) originally developed by Gary Gygax and Dale Arneson. It developed from the epic scale of table top war gaming, but the story was brought down to the level of individual heroes. Although it relied heavily on the mechanics for combat and task resolution, story telling and character/player interaction was central to the game. Its success led to an explosion in RPG games. D&D is still available, now published by Wizard of the Coast and is in it's 5th edition.
The assigned date of its release is a bit of a conjecture based on anecdotal references.
http://playingattheworld.blogspot.com/2013/12/when-dungeons-dragons-turns-40.html