Its also called Lateral thinking exercises.
Edward DeBono - Father of lateral thinking.
they taught this technique when i was studying architect and it does work very well.
Essentially have lots of crazy lateral ideas, resist the urge to converge them.
they take the many lateral ideas and start to converge them, and see which ones turns out the best.
The nice thing was that in Edwards DeBono's books there were many methodologies that you can employ to stop your mind converging the ideas. You see we naturally always try to converge ideas, which shuts down the possibilities