Make Your Own Kaleidoscopes
I went with a patriotic theme for my example kaleidoscope. One thing I like about these kits is that they come with 25, so you can do your example and still have an even two dozen.
I like these kits but they do take some prep work. Since I knew I would likely have smaller kids coming to this event, some steps (like folding the acetate paper into a triangle and taping it together) would be hard for them. So I pre-assembled a lot of the steps beforehand. That also enabled me to use a hot glue gun on each of them, instead of the tape that came with the kit (which definitely would not cut it).
In fact, I didn't use the tape that came with the kits at all, and instead put out washi tape. I also added beads and sequins to the beads that came with the kit.
After simplifying the process, I made these instructions for each table.