This origami Cuckoo Clock, by artist Robert Lang, is folded from one uncut 1x10 piece of paper. As outrageously amazing as that is (and as much as I love cuckoo clocks), I think I prefer a couple of Lang's other works. Like this Allosaurus, folded from 16 separate squares of of paper...
Or the stag beetle, folded from one uncut sheet:
• A few of Lang's origami crease patterns
• Lang's Idea + Square = Origami at TEDtalks (YouTube)
• Lang Interview (Google Video)