1) SpongeBob SquarePants was originally titled SpongeBoy, but Nickelodeon had to change the name because a mop company had already trademarked it.
2) The show was created by Stephen Hillenburg — a former marine biologist who went back to school to study animation.
3) Hillenburg says he never expected the show to take off. He even once admitted in an interview: "I really figured we might get a season and a cult following, and that might be it."
4) The original concept had SpongeBob as an actual sea sponge — but Hillenburg later changed him to an artificial, rectangular sponge because he thought it would be funny. To make things even stranger, Hillenburg kept SpongeBob's parents as actual sponges.
5) To pitch the show to Nickelodeon, Hillenburg created miniature versions of the main characters and put them in an aquarium together. He brought the aquarium to the pitch meeting, and wore a Hawaiian shirt during his presentation.
6) You might remember that live-action pirate dude, Patchy the Pirate (pictured above). He's portrayed by Tom Kenny — the very same dude who voices SpongeBob.
7) Kenny also provides the voice for the French narrator guy — the one who says things like "Two hours later." And he voices Gary the snail!
8) Hillenburg wrote the part of SpongeBob specifically for Tom Kenny, based on a voice he'd heard the actor do on Rocko's Modern Life. “I don’t think anyone else even read for the part," Kenny once revealed. "SpongeBob SquarePants was the easiest job I ever got."
9) Kenny says his worst fear is that someone will punch him in the vocal cords and he won't be able to voice SpongeBob anymore.
10) And Hillenburg has said that his biggest nightmare is finding SpongeBob merchandise washed up on a beach, since he's a former marine biologist and doesn't want to contribute to ocean pollution.
11) In real life, Kenny is married to Jill Talley, the actor who voices Karen the Computer.
12) Bikini Bottom is named after a real-life place in the Marshall Islands of the Pacific Ocean called Bikini Atoll. The United States carried out nuclear tests in Bikini Atoll throughout the '40s and '50s.
13) This fact has led to a popular fan theory that the characters of SpongeBob are all radioactive mutants. Tom Kenny has denied this, though.
14) The Krusty Krab building is actually a lobster trap. And Mr. Krabs is based on a former boss Hillenburg had when he worked at a lobster restaurant in Maine.
15) In interviews, Kenny has admitted that he's totally shocked by the amount of SpongeBob merchandise he's seen out in the world, including SpongeBob tampons and surgical masks.
16) In early episodes, Plankton was so tiny that you could only see him with a magnifying glass. Animators decided to enlarge him later on in the series, to make it easier for him to interact with SpongeBob and the gang.
17) The actor who voices Plankton, Mr. Lawrence, says he got the inspiration for the character's voice from a few different sources, including Tony the Tiger and the guy who sings "You're a Mean One, Mr. Grinch."
18) Patrick's character was initially conceived as a bully who was constantly angry about being pink. The show's creators quickly did away with this idea.
19) SpongeBob's iconic laugh is based on the sounds of a dolphin wail.
20) Every 11-minute episode of SpongeBob takes almost an entire year to complete, from start to finish.
21) SpongeBob episodes are written and recorded in Los Angeles, but animated by a studio in Korea. "Sure there's communication barriers, but those guys work really hard and have some talented cartoonists on board," Hilleburg once said in an interview.
22) Hillenburg was initially opposed to doing any SpongeBob movies, turning down Nickelodeon's repeated requests for over a year before finally giving in.
23) Justin Timberlake was tapped to perform a song for the first SpongeBob movie, but Hillenburg rejected the idea, allegedly calling the pop star a "commercial weirdo."
24) Hillenburg says he hates when SpongeBob does promotional tie-ins with fast food brands. Whenever those promotions happen, Hillenburg has a rule that SpongeBob isn't allowed to directly interact with any of the products.
"[W]e didn't want to suddenly become the people serving up food that's not that good for you — especially kids," he told the New York Times.
25) Patrick Star is voiced by Bill Fagerbakke, who you might also recognize as Marshall's dad on How I Met Your Mother (see above!).
26) Carolyn Lawrence, who voices Sandy Cheeks, was discovered by a Nickelodeon casting director on a random sidewalk in LA. The director thought she had an interesting voice and asked her to come in for an audition.
27) Unlike most animated shows, SpongeBob records each episode with the whole cast together in room, instead of taping each actor separately.
28) According to Kenny, there's a lot of improvisation between the cast during recording sessions: "We do try to add jokes, we do a scene a bunch of times, with as many variations as possible."
29) And finally, Kenny says he has a lot of love for his fellow castmates: "We all like each other, and for good reason. We’re all nice, functioning people, by showbiz standards, anyway. We’re functionally insane. We’re a ragtag group of misfits, but we’re pretty good at life."