This page is still in undetermined format.
The idea is to leave links to challenges I have come across and enjoyed seeing results others linked up, whether or not I have participated.
Mittens had a challenge for using the Book Covers after all the pages were used on other projects.
The Creative Every Day Challenge is an ongoing challenge site with monthly themes. You can interpret any way you choose and join at any time.
Feline Playful has a nice comprehensive listing of challenges.
The Let’s Get Shabby challenges leave one open to a wide variety of interpretations.