Haha.....I saw those in The Washington Post. My wife bought me a couple of adult coloring books for Valentine's Day and they really do relieve stress. I would have never imagined how much I lost myself into coloring. One of the books is The Enchanted Forest which is really cool. The other one has designs with sort of an India bent to them.
I actually only like children's coloring books. I have fine motor skills issues and I still literally have the coloring/drawing skills of a toddler because of that, so I'm not good at all at coloring in the big complex pictures that are in adult coloring books. Plus, the kid ones just feel more "little" to me (naturally.) Some of the adult ones have cool pictures though.