I have used this with my second grade class for many years. Parents are asked to write a secret letter to their child. Parents do not sign their name or write "Dear Sally". The letters are posted on the white board on Valentine's Day. Students must read to find clues as to which letter their parent sent. After reading the letters some students may still have trouble finding their letter. I call the students back to their desks and have them all stand. I read each letter out loud. If I read a statement that does not describe them, the student sits down. I usually have only one student standing with a huge smile!
Yes, I have sadly written only a few letters for "dead beat parents."