I can think of at least one other -- In "Bang a Gong (Get it On)" by T. Rex, you can hear one part where a background singer starts to repeat the chorus one time too many, and gets roughly to "Get it o-" Oh, and supposedly John Lennon accidentally sang "Desmond stays at home and does his pretty face" in "Ob-la-di Ob-la-da" (reversing the lines) and they thought it was funny so they recorded the verse both properly and reversed.