I found a wonderful article about Adult coloring at Squidoo.com written by Pastiche
Pastiche is a visual artist who draws coloring pages for grown ups and kids plus creates clip art and commercial graphics.
When I was working I never actually added coloring to my calendar, but had material available for those that wanted to do something on their own or in between activities. After reading this wonderful article on coloring I am thinking it would be a great activity to add to any calendar. Click on the link above to find very useful information about Adult Coloring.