Near the end of the year, I give all of my English class students an envelope and instruct them to write a letter to themselves, to put it inside the envelope, and to address it to themselves. Then I tell them that I will mail it to them in five years, and I do.
I always include a letter from myself telling them what is going on with our family, and I put that inside their letter as well. It is so fun to see their handwriting once again after five years, and to read the funny things they wrote. Sometimes they seal their letters. Then I just leave them sealed and put my letter in another envelope that I address to them.
One of the benefits of this is that I always hear back from some of them. After I sent out the last group of letters, I heard from former students who were getting married, starting their own little business, or going off to the Middle East to learn Bible translation. That is exciting to hear about.