I'll get some not-specifically-building-related-but-cool-nonetheless stuff out of the way first. Came across this guy on the side of the road in either Michigan's upper peninsula or a bit more north in Canada. Seems to me it was about the same time I stopped in at Da Yoopers Tourist Trap.
After the Colloquium-East in '98, I stayed a night at the house of a crazed landscaper inspired by Andy Goldsworthy. These are about the coolest stacked rocks I've ever seen in person.