RubyDung

RubyDung was a game created by Notch before Minecraft. Not much is known about the game other than it is influenced by Dwarf Fortress. The Grass and Cobblestone textures that were used in this game were later used in Minecraft. It is one of Notch's inspirations to create a block-styled game, which later turned into Minecraft. Despite not actually being RubyDung, early pre-classic versions of Minecraft are referred to as "RubyDung" internally. This was before Minecraft had a proper name.

On October 30th, 2009, Notch talked about RubyDung on his blog in an entry entitled The Origins of Minecraft.

RubyDung