One concept which has been in focus in game AI research is procedural content generation. What it means is, generation of gameplay objects and environment dynamically based on user actions and inputs. This includes from things like changing story based on user action or the topology of the environment based on time of the year. More information of this here.
One of the games, which applies PCG to a large extent is audiosurf. In the game you have to surf your ship through the course while avoiding the hurdles in the way. The path you travel, speed of travel and the obstacles are generated using the beats of a song which you can select before starting to play the game. The is available on Steam, I encourage all of you to definitely try out the free demo. See video below.