What are some good, easy to play songs for a campfire?

I'm going to a cottage this summer with my family, including my aunts
and uncles, and 4 of my younger cousins (all under 8 years old). We
always have a campfire on Canada Day, and I'm thinking of playing a
song while we roast marshmallows. What would be some age-appropriate
songs for this?

I already know spongebob's campfire song, and 7 8 9 by the Barenaked
Ladies.

Thanks :)