Anthony is really into coloring things "rainbow." As a matter of fact, he asks me why I don't color "prettier" when I color something just one color :) First-School, a free website, has these sheets along with mini-books, and several ideas for every letter, including some combinations of letters (such as Ch, etc). It has really come in handy for us for reinforcement as well as working on fine motor skills, such as coloring, cutting, and pasting. We use these activities when all of the "meat and potatoes" of a lesson are complete, as a reward. Find them all here: http://www.first-school.ws/theme/alphabet.htm
We also sometimes "free style" with reinforcement projetcs, as you can see with our igloo, for "I."
Here are some examples: