15 years ago today, we finally learned the cause of Homer Simpson’s sub-normal intelligence. “The Simpsons” episode “HOMR” gave us an answer as to how Homer could get his arms stuck in not one but two vending machines and forget the word for spoon (“that metal … dealy… you use to… dig… food?”).

In that season 12 episode — which aired on January 7, 2001 — an x-ray reveals that Homer has a crayon lodged in his brain that’s been there since he was six years old. When Homer gets the crayon removed, his IQ skyrockets, and he’s suddenly no longer the village idiot. But once he realizes he’s happier when he’s dumber (despite a newfound connection to his intelligent daughter Lisa), he has the crayon re-inserted into his brain.

Other notable January 7 happenings in pop culture history:

• 1929: The comic strip “Buck Rogers in the 25th Century” (then called “Buck Rogers 2429 A.D.”) made its first newspaper appearance.

• 1950: Gene Autry’s “Rudolph, the Red-Nosed Reindeer” hit No. 1 on U.S. charts.

• 1982: The “Fame” TV series debuted on NBC.

• 1983: The 100th episode of “The Dukes of Hazzard” aired on CBS. 

• 1992: Eric Clapton released his single “Tears in Heaven,” which he wrote to express his grief after the death of his four-year-old son.

• 1994: Nirvana played a show in Seattle. It was their final U.S. concert. Nirvana frontman Kurt Cobain died the following April.

Birthdays: “National Treasure” actor Nicolas Cage (turns 52 today), “CSI: Miami” actor David Caruso (60), “The Walking Dead” actress Lauren Cohan (34), television host Katie Couric (59), “Agents of S.H.I.E.L.D.” actor Brett Dalton (34), “Agent Carter” actress Lyndsy Fonseca (29), “Life of Pi” actor Irrfan Khan (49), singer-songwriter Kenny Loggins (68), “The Hurt Locker” actor Jeremy Renner (45), “Misfits” actor Robert Sheehan (28), “Nurse Jackie” actress Merritt Wever (36)

An enthusiast of time travel stories, film scores, avocados and Charades, Emily Rome is an alumna of Loyola Marymount University and a native of beautiful Washington State. Emily’s writing has also appeared in the Los Angeles Times, Entertainment Weekly and The Hollywood Reporter. Follow her on Twitter @EmilyNRome.