Grandfather's Clock and The Cat Came Back are some of my favorites!!! Both ones I've heard recently as well on children's cds we got from the library.
Tom Paxton's The Worms Come Crawling Underground is one we recently discovered via "children's cd" at the library. It's from 2008, so they are still making questionable kids songs. And, maybe I'm just odd, but I love this type of song (actually I got a kick out of his whole cd):
https://www.youtube.com/watch?v=hivHyebyNQo
Then again, I've also subjected my own children to:
The Cat Got Dead
Cows With Guns