I started writing lunchbox notes to Taylor in preschool.  She loved it so much that I haven't stopped… and this year I started the tradition with Payton.

I covered the top of their sandwich containers with chalkboard vinyl (found at Hobby Lobby).  I use chalk markers to write.  They wipe off easily with a wet sponge.

For Taylor (2nd grade), I write riddles and jokes.  I print off lists of jokes and riddles that I find via Pinterest so I don't have to think about what to write at 6:00 in the morning.  Since Payton (kindergarten) is still learning to read, I do more drawings with just a few words that she can read.  They both seems to look forward to what their note will say each day so it makes it worth the few extra minutes of prep each morning.