Remember the Christmas chains that you used to make when you were little? And then you made them with your kids when they were little? Every night, after prayer we would run to our chain to remove yet another link as the days slowly marched by. It seemed like Christmas would never arrive. Now as an adult, time seems to fly by. This activity is a variation of the Christmas Chain that I'm sure your missionary will remember from their childhood.
I purchased the paper for the chains from Oriental Trading. You could always cut your own strips of paper if you'd like but these were incredibly inexpensive and I've used the same pack for the last three years. They come in two different styles - plain red and green, or candy-striped. Each set comes with 500 pre-cut, pre-gummed strips for $5-$6 depending on the style you choose. Moisten gummed ends to form each link. No stapler needed. Brilliant!
We worked on this activity at our family Christmas party this year. Everyone took one link and wrote a message on the inside. Then they connected up their links making one long chain. Our chain fit easily into a small Flat Rate mailing box. I included a note telling our missionaries to count how many days until Christmas and remove and read any additional links. Every night thereafter they can read a short message from home leading up to Christmas.