We enjoyed many sing-alongs in elementary school but there were two I've never forgotten.
Who Stole the Cookie from the Cookie Jar (or the Cookie Jar Song) was my one of favorite tunes in Kindergarten. It was one of those sing-along games that could go on and on. It was also a great way to learn names and make friends. Remember these lyrics (via Wikipedia)?
Accuser: Who stole the cookie from the cookie jar?
(name of a child in the circle) stole the cookie from the cookie jar.
Accused: Who me?
Accuser/Group: Yes, you!
Accused: Not Me, Couldn't be!
Accuser/Group: Then who?
Accused: Name of another child in the circle (and so on).
I must admit, at the time, that was pure bliss.
The other sing-along that I recall vividly is Down by the Bay. It was definitely the more creative of the two songs and encouraged kids to be inventive. The lyrics (via Wikipedia):
Down by the bay (repeat),
Where the watermelons grow (repeat),
Back to my home (repeat),
I dare not go (repeat),
For if I do (repeat),
My mother will say:
A variation on "Did you ever see a _____, _____ing a _____", with rhyming words, for example:
"Did you ever see a goose, kissing a moose?"
"Did you ever see an ant, climbing a plant?"
Good times, good times.