Procedural content generation has been applied to video games forever to create random content and to reduce the space requirements for games. Roguelikes are a genre that generally depend on procedural generation for level creation. And recently, Will Wright’s Spore has put this idea in the spotlight, since the game is mostly procedurally-generated.
But all in all, I think this is a concept that is still relatively unexplored, and it could be applied creatively to every part of a game to do some really neat stuff! The focus of this competition is to develop a 4-week game that uses PCG to create compelling, new content every time the player starts a game.