Garry's Mod Sells 10 Million Copies
Unsurprisingly, a sequel is currently in development.
We'll begin emailing you updates about %gameName%.
Jesus christ. GMod sold its ten millionth copy over new years.— Garry Newman (@garrynewman) January 2, 2016
The $10 Garry's Mod, as its name suggests, began its life as a free mod for Valve's Half-Life 2. As IGN notes, the standalone version was released in 2006 as part of Newman's formation of Facepunch Studios.
A sequel to Garry's Mod is currently in development, though, as of September 2015, it's still "early days" for this game. Virtual reality will be a "big point" of this game, which will not be called Garry's Mod 2.
Never tried Garry's Mod? It's marked down to just $2.50 right now as part of the soon-to-end Steam Winter Sale.