I have always used this simple activity to just fill-in when I heeded it. I have used it for world history, American history, Louisiana history, reading, and art classes; anything that I have taught over my years in teaching. Generally I grade them for my student's accuracy and completion – missing one letter is an A, two letters a B, three letters a C and so on. As long as I could find an example for a letter, so should they.
This can be used for most any subject, almost any age group.