If there is one class activity that your students will remember for the rest of their lives it will be this one - a Tzitzis tying workshop.
In the Torah Live series on "Tzitzis" there is a video titled "How to Thread Tzitzis"
We recommend to first watch this video with your students and then to bring enough pairs of tzitzis + strings for the students and setup a "workshop" in your class.
Below is a workshop that Rabbi David Pietruszka from the Jewish Education Center in Elizabeth, New Jersey did with his students:
If you did a Tzitzis tying workshop with your students - we'd love to see it, shoot us a message in the chat!