I don't understand the coloring book concept. I wonder if it is an American thing [I am from Europe], especially the recently successful "adult coloring book" concept. Personally I find inconceivable that someone can spend his time doing this. Unless, of course, it's just a pretty excuse for using B/W printing which is cheaper than full color, or you put special meaning in the activity -- apparently some consider it a form of meditation.

Even for kids I have doubts. I remember I once talked to an American 12-year old that loved to color books and at that time I found incredible that too: in my european world, coloring books are for pre-schoolers.