Clever little Easter eggs in this article about the history of My Fair Lady refer to lyrics from the show.

I played Col. Pickering in high school 30 years ago. One night during “The Rain in Spain,” when Higgins threw the xylophone mallet in the air, it got stuck in the drapes above the stage. I had watched it go up, so the audience laughed when I waited for it to come down and nothing happened. I saw it slowly working its way loose right above my head, but pretended to give up and went on with the song. Then, a few seconds later when the mallet did come down, it hit me on the shoulder right during the line “And where’s that blasted rain? / On the plain! On the plain!” At that moment I reached out and hammed a befuddled, now-where-did-that-drop-come-from? gesture. The audience loved it.

The musical has some of the best-known songs in Broadway history, but it originally had other tunes that almost no one knows. Some of those songs were recently performed for the first time in decades.[…]

If you want an audience to beg for more, you can’t actually dance all night, so after the very first preview in New Haven, Conn., the composers cut another 15 minutes of material. It came right after flower girl Eliza Doolittle made her disastrous debut at the Ascot Races. She was ready to quit her lessons, so linguistics professor Henry Higgins, played by Nathan Spencer at the University of Sheffield, enticed her with visions of triumphs to come. The song that followed, “Come to the Ball,” was performed exactly once by Rex Harrison at that first preview 59 years ago

—NPR