Dungeons & Dragons co-creator Dave Arneson, whose fantasy role-playing game guided the socially awkward through adolescence, has rolled his last dice. Arneson, the Associated Press reports, died on Tuesday of cancer in St. Paul, Minn., at the age of 61.

He and Gary Gary Gygax – who died last March -- invented D&D in 1974, and the game became a cult favorite among geeky teen boys, giving way, as ScientificAmerican.com tech editor Larry Greenemeier notes, to the nerd power of the 1980s embodied by Bill Gates. (It is also a favorite of a number of actors, including Vin Diesel, who describes how he would battle orcs, the game’s common bad guys, here.)

D&D players made up medieval characters that engaged in adventures through a complicated set of rules and 20-sided dice. As D&D producer “Wizards of the Coasts” puts it, the game is “part acting, part storytelling, part social interaction, part war game, and part dice rolling. You and your friends” – one of whom plays the role of the Dungeon Master – “create characters that develop and grow with each adventure they complete.”

D&D inspired a wealth of similar games and an early Tom Hanks TV movie, Mazes and Monsters. Arneson "developed many of the fundamental ideas of role-playing: that each player controls just one hero, that heroes gain power through adventures, and that personality is as important as combat prowess," Wizards of the Coast said in a statement on its Web site.

Dungeons & Dragons dice/Franganghi via Wikimedia Commons

*Editors' note (4/13/09): Thanks to our readers for bringing to our attention that the original image posted with this blog did not properly illustrate the story.