I love coloring....I found pages of free mandalas to print online and for about half of my last semester at school they kept me occupied during class; I've always needed to do something with my hands to pay attention better and in the past I would doodle, write notes to friends, or whatever. Once I found the mandalas, it was perfect; I got some colored pencils and got going. They kept me occupied, let me play around with color theory while being art that I didn't need to "do" much for, and afterward they look pretty on my wall. I haven't gotten much done this summer as I haven't been sitting for long periods doing them, but it's fun anyway.
Recently I also found a site that has quilt patterns to color so I plan on playing with those too.