This is one of the best shows ever. If you ever thought that the level of intelligence and imagination of a person could never go far beyond your own, you should watch this and there is a chance you might stand corrected. Most people are put off by the anime tag but a lot of things in this comes of far better when shot as an Anime as opposed to real human. There is a real movie version of this but that does not even come close to this.
After watching this, I was searching the entire Anime world for something similar and could never find anything as good as this.