I loved the NCTM article from Teaching Mathematics in the Middle School called "Masterpieces to Mathematics." (Link: http://mason.gmu.edu/~jsuh4/math%20masterpiece.pdf)
In the article, the teacher shows a new way of approaching representing fractions, decimals, and percentages.
I used this activity in my 11th grade test prep course to support student understanding of fractions. The teacher in the article used the lesson in her middle school class. The first thing I did was look up Ellsworth Kelly's piece Colors for a Large Wall and brought color field art, op-art, and hard edge art into the classroom through a short slideshow. The coloring activity kept my students busy and interested. It was easy enough for review, but a good resource to use when students are getting the hang of converting between fractions, decimals, and percentages.
You can choose to change the grid from 64 squares to 100 squares to make the assignment less challenging.