I did this with 3rd grade students for our second last activity before their graduation, and I could say, they really enjoyed it!
Preliminary
Start with distributing a piece of paper, with the size just enough for them to write their full name. Let them pass the piece of paper and put it in a box to get ready with the drawlots.
Goal
Explain the activity's goal: To write a letter to someone without telling it to anyone
Note: They can't choose who they want to write a letter to, but whoever they pick from the box
Message
Give the essential parts of the letter. You may customize according to your class' level and interest.
We did three parts:
something good about the student (or something admirable about that student);
a memory with the student (funny memory, sad memory, good memory, anything unforgettable);
good luck message for the future
Letter
Distribute the letter. Tell them to think of their code name. They are not allowed to write their name as the sender, neither an obvious code name. Tell them to write the full name of the receiver the last before they pass it to avoid some seatmates from peeking and finding out to whom the letter will be.
Drawlots
Give the box to the student in front from the left or right then let them get one paper (containing the names) and pass. ALT/JTE may join to make it more exciting.
Writing Time
Give enough time to write. Assist students if they need it.
Pass
Let each one put the letter infront, on the desk, face down, safe enough from others to see.
Letter-Giving Time
ALT/JTE take turns in reading the receiver and sender (code name) of the letter. When they hear their names, they have to come forward and get it from the teacher.
This sounds so cute!! Just wondering if you had any students that were hesitant to write to the person they picked, whether it was because they don't really hang out or were just embarrassed to or something?
Yes, so far, I only had one student, considered under special class, who told me she never talked with the person she picked. In that case, I just helped her with what to write :)
Perfect, thank you!! I think I'll try it out :)