A Unique Billboard Inspired Conan O'Brien To Write The Simpsons' Legendary Monorail Episode

"Marge vs. the Monorail" remains a memorable outing for "The Simpsons." Between the unctuous and oily Lyle Lanley (the late Phil Hartman in a performance full of Broadway-sized razzle-dazzle), an iconic musical moment, and Leonard Nimoy putting in a fun guest-starring appearance, it's quite the legendary episode. 

"Marge vs. the Monorail" features a genuinely suspenseful plot that sees Marge Simpson (Julie Kavner) trying to put the breaks an overfunded (and shoddily constructed) monorail that has been sold to Springfield by the charismatic traveling conman Lyle Lanley. Once she finds out what happened to North Haverbrook, which fell for Lanley's pitch before Springfield and built a monorail that bankrupted the town, she's in a race against time to stop the monorail before it plunges Springfield into financial ruin and possible disaster.

Over the years, the reputation of "Marge vs. the Monorail" has only grown. It's been ranked among the show's best outings: IGN named it the show's best episode out of a slate of 34 picks in 2022, and Variety named it the show's second-best episode in 2021 out of a field of 30. The episode was written by Conan O'Brien, then just a "Simpsons" staff writer. You'll be surprised to learn what inspired him to come up with the plot behind this legendary outing. And no, it didn't involve encountering a possum called Bitey.

In a deep dive into the episode from The Ringer, Conan O'Brien said that the initial kernel for this iconic "The Simpsons" episode came when he drove by a billboard with a single word emblazoned upon it."It just said, 'monorail.' I don't even know why," he said. "Monorails were always funny to me because they're a phony promise of the future. It really is just a trolley, right?"

O'Brien was so inspired by the billboard that he scribbled down the phrase, complete with an exclamation point. From there, he crafted a plot in which Springfield gets scammed by a smooth-talking conman, and eventually, O'Brien pitched it to Richard L. Brooks at a writer's retreat. The pitch garnered him a huge laugh, and he got the chance to write the episode, to his expressed shock and disbelief. "I felt like, 'Oh, this is such a me kind of idea that I had an ego about. I really hope this gets done, I'm very excited to see it if I can, and what's the monorail going to look like?' I couldn't believe this could really happen," O'Brien explained.

O'Brien also penned the lyrics to the "Trouble"-esque tune "The Monorail Song," for which he collaborated with fellow staffer Jeff Martin. To get the beats of the parody song just right, he closely studied the soundtrack for "The Music Man." His hard work paid off and resulted in a thoroughly memorable episode.