Yeah, I know. Another short one.
Dave Arneson, creator of Blackmoor, co-creator of Dungeons and Dragons, and the first GM as we know the term today, died late April 7, 2009.
While not the household name that E. Gary Gygax was, without his simple innovation to the Chainmail rules, campaign worlds, D&D, and likely role-playing games in general, from paper-and-pencil to computer MMORPGS, would not exist.
He died at the age of 61 from cancer in St. Paul, Minnesota.
Longer obituary here.