Actually, Tom Chapin used "Sesquipedalian," and several other biggies, in his kids' song "Great Big Words."

"They look at me like I'm an alien
When I say words like sesquipedalian.
But what me worry, can't go wrong
With a word that's a foot-and-one-half long.

Great big words, I like big words.
No extra charge if it's very large,
Great big words."