15 Images You Won't Believe Aren't Photoshopped, they had a few interesting pieces in there, even a link to the house posted above.
As well as number 11 on their list. "Yes, if you stand in this spot in the parking garage shown in the photo, the word "DOWN" is just floating there. The sign was designed by an artist who won an award for it, because there are apparently awards for making innovative signage in parking garages.
He created the effect of continuous letters by adjusting the angles for appropriate perspective as they reached walls, just like in those incredible chalk sidewalk drawings that are all over the web."
I followed one of the links on the Cracked site, to the Mighty Optical Illusions weblog. Which has a plethora of some spectacular photos.