Happy Birthday: Ernest Gary Gygax (July 27, 1938 – March 4, 2008) was an American game designer and author best known for co-creating the pioneering tabletop role-playing game Dungeons & Dragons (D&D) with Dave Arneson.

In the 1960s, Gygax created an organization of wargaming clubs and founded the Gen Con gaming convention. In 1971, he co-developed Chainmail, a miniatures wargame based on medieval warfare with Jeff Perren. He co-founded the company Tactical Studies Rules (TSR, Inc.) with childhood friend Don Kaye in 1973. The next year, he and Dave Arneson created D&D, which expanded on Gygax's Chainmail and included elements of the fantasy stories that he loved as a child. In 1976, he founded The Dragon, a magazine based around the new game. In 1977, he began work on a more comprehensive version of the game called Advanced Dungeons & Dragons. He designed numerous manuals for the game system, as well as several pre-packaged adventures called "modules" that gave a person running a D&D game (the "Dungeon Master") a rough script and ideas. In 1983, he worked to license the D&D product line into the successful D&D cartoon series.