After watching how mesmerized she was while filling in the images with her newly sharpened pencils, I decided I wanted to color as well. Although the images I colored werent exactly inspirational to me, I enjoyed the experience overall. The next day, I decided I wanted to get my own coloring book with a new set of colored pens. I bought a book full of pictures of mandalas (a circle with complex designs in it). The designs were beautiful and I could imagine them once I filled them with color.
You have a greater tool - your PC - that can be helpful to get the printouts of diverse colorful sheets. Guide the children, exclusively during the holidays to add illustrations to the colorful-page, and showcase them around the prominent places of the house. This will give them, a sense of pride and joy for their creativity, and would lead to further productive pursuits. Thus, you will witness that there are massive advantages of coloring-page relatively to coloring books. Coloring sheet are economical, costing you only a couple of cents in ink and paper rather than a few dollars for a coloring book.
You can metaphorically take a page out of a coloring book, and break up the work into a few sections. Each team member or group within the team should first be instructed on which part of the page they are going to color, let them know what color they can use, and when their turn will come up. Next, after each team member has finished their part of the coloring than take the completed picture and hangs it up so that every one can see their part of the picture and the entire teams contribution.