The Day the Crayons Quit: 10/10/13
The Day the Crayons Quit by Drew Daywalt is about the dangers of falling into an artistic rut. Duncan is an elementary school child and enthusiastic artist (and perhaps as prolific as B.B. Gunn from the Wayside School books by Louis Sachar) whose crayons have gone on strike.
In their place on his school desk, Duncan finds a small pile of letters. Each one is from one of his former crayons. Red is Duncan's favorite (and most abused) color. Purple's a bit of a neat freak and wants Duncan to stay in those lines! Gray is worn out (and down) from all those elephants, hippos and rhinos. White is tired of being invisible (since he only ever uses white paper). Pink wants more use and not just for princesses. And so on and so forth.
What the book most reminds me of is Nick Bantock's Griffin and Sabine epistolary series. Bantock created postcards and stamps to show the correspondence between a man and a woman separated by an ocean. Here the correspondence is between Duncan (through the samples of his artwork) and the crayons, through their letters (written, of course in the color of the letter's author).