Meet Finn, he's one of the new heroes in Star Wars: The Force Awakens. He starts off as a Stormtrooper.
He's pretty low in the ranks, he works in the sanitation department and has only seen battle once. He doesn't even have a real name, just an identification number: FN2187.
Later, after his friend smears blood on his helmet like Simba in The Lion King, FN2187 realizes the Dark Side is bad and he defects. He gets a new name from his new friend Poe Dameron: Finn. It's like FN, but cooler, ya know?
But J.J. Abrams is a crafty man, and he likes giving little nods to Star Wars superfans. So FN2187 couldn't just be a random number. It had to mean something.
BUT WHAT COULD IT MEAN? A date? February 1, 1987? A birthday? An important day in the Star Wars universe?
Turns out, it's even more obscure than that. Remember all the way back in A New Hope, when Princess Leia gets captured by the Galactic Empire and she's held captive?
Well, when Luke and Han go to rescue her, Han says which cell number she's being held in. And guess what the cell number is: