Garth Brooks-
Instead of "I'm Shameless"
I hear "I'm Shavin", which actually improved the song!

Shawn Colvin-
On "Set the Prairie on Fire"
instead of "How far will it go" I heard
"I fart and let it go", which still cracks me up for some childish reason.

In the spirit of true confessions I'll admit to this last one, but please be gentle: On the "Gummy Bears" theme song when I was young I (as well as my sister) heard "High adventures beyond compare" as "I can see their underwear"