Best Way to Sell Game Concepts

dunng808 writes: "If a couple of young, game crazy guys wanted to get started designing a game with the intention of selling the concept, how should they proceed? In the music industry they would make a demo mp3. In the film industry they would write a script, and I would recommend lyx with the hollywood document class. Should they develop some sample game play with a well-known engine? Is the one in Blender good enough? This somewhat dated list suggests it is. Or should they focus on textual descriptions and static scenes made with Blender and the Gimp? Is there even a market, much less a convention, for selling game concepts?"