I created this lively and colorful mini book made with ATC sized pieces of art. It didn't start out as an 'ATC book'. I was just too lazy to cut other sized papers and have hundreds of ATC backs already cut. It's called a 'Poetry' book because the backs of each page are blank to include a person's favorite poems. This is now a sweet kit over at Altered Pages. Did you see my House ATCs made it into a kit as well?
My favorite part of the book was stitching this velvet ribbon interlaced with rock beads.
It's sort of a freeform book with no discernible edges or shapes, although it is near an ATC size.