Thanks for the MacGonagall post- I haven't seen that poem for years and it had me almost falling off my chair laughing.
I'd like to contribute these two:
In "The Sound of Music" Rogers & Hammerstein almost manage to rhyme "adieu" with "you":
to yeu and yeu and yeu"
... and in Burt Bacharach and Hal David's "What do you get when you fall in Love?" the otherwise indominatable pair have this classic:
"What do you get when you kiss a guy?
You get enough germs to catch pneumonia
And after that he'll never phone yer,
I'll never fall in love again..."