Not only did Thorsten Bonsch spend a year of his spare time constructing a gloriously macabre LEGO rendering of Arkham Asylum, he also released an 82-page, step-by-step making-of book that you can download for yourself.
Let's be clear though, these are detailed instructions along with a description of the architectural inspirations for the facility—a 115.5 megabyte file [Hotfile download] that'll take 20 minutes to download. But if you've got the bricks and the brains, the manual will show you how to make one of your own.
Plenty of cameos and homages abound in this diorama—you can easily spot the foliage bloom from Poison Ivy's shattered cell. [An even bigger version is here.] It's the work of a mad genius, for sure.
The full size rendering is below. Enlarge it by clicking the magnifying class icon at upper left. What features do you see?
The Elizabeth Arkham Asylum for the Criminally Insane [The Brothers Brick via Game Informer]