This looks very obvious in hindsight, but I am sure not many would have thought about this. This guy uses the HL's source engine to produced a model of the Kaufmann House by Frank Lloyd Wright. Using the Source Engine, as opposed to more traditional Architectural Software, allows the use of dynamic lighting and a real-time walkthrough of the scene in high resolution.
Links: the HL map for Kaufmann House and a walk through available here
Comments
I had not heard of the Kaufmann house before this day and guess what, I ran a search on Wikipedia. And lo ... I found THE SOURCE! Get it?
BTW have you chanced upon to play the game powered by this awesome engine yet?