Everyone knows the best way to spread Christmas cheer is singing loud for all to hear! But the second best way is to enjoy Elf. Revel in the giddy glow of this modern holiday classic with a slew of secrets from behind the scenes.

1. Jim Carrey was initially eyed to play Buddy the elf.

When David Berenbaum's spec script first emerged in 1993, Carrey was pre-Ace Ventura: Pet Detective and attached to front the Christmas film. However, it took another 10 years to get the project in motion, at which time Saturday Night Live star Will Ferrell was signed to star. Carrey would go on to headline his own Christmas offerings—the live-action How The Grinch Stole Christmas and the CGI animated A Christmas Carol.

2. Will Ferrell worked as a mall Santa.

Warner Bros.

And his A Night at the Roxbury co-star Chris Kattan was his elf. This was back when the pair were pre-Saturday Night Live, and part of the comedy troupe The Groundlings. Ferrell recollected to Spliced Wire, "I have some experience playing Santa Claus … Chris Kattan was my elf at this outdoor mall in Pasadena for five weeks, passing out candy canes. It was hilarious because little kids could care less about the elf. They just come right to Santa Claus. So by the second weekend, Kattan had dropped the whole affectation he was doing and was like (Ferrell makes a face of bitter boredom), 'Santa's over there, kid.'"

3. Director Jon Favreau favored practical effects.

Inspired by the Christmas specials he grew up with, Favreau explained in the film's commentary track that he employed “old techniques” instead of CGI whenever possible. This included stop-motion animation, and using forced perspective to make Buddy look like a giant among his elf peers. For North Pole scenes, two sets were built—one larger scale for the actors playing elves, the other smaller to make Buddy and Santa look big. These elements where then carefully overlaid in camera, using lighting to blend the seams.

4. Snow was often computer-generated.

Warner Home Video

Some effects just couldn't be practical. These included the snowflakes that drift over the opening credits, and many of the snowballs in Buddy's pivotal fight scene. It's probably not much of a shocker that much of these were added in post, considering Buddy's perfect aim. But to further underscore the drama that is a snowball fight in frosty New York, Favreau asked composer John Debney to give this section a Western vibe that would recall The Magnificent Seven.

5. Elf's production design was heavily influenced by Rudolph The Red-Nosed Reindeer.

The classic stop-motion Christmas special from 1964 gave a memorable presentation of Santa's winter wonderland to which Favreau wanted to pay tribute. The elves' costumes in Elf were inspired by those worn by Hermey and his peers in the animated film. And Elf's workshops were modeled after the Rankin/Bass designs, as were the stop-motion animals of the area. The production did secure permission for these allusions, and was even granted the privilege of using the company's signature snowman.

6. There's a Christmas Story cameo.

Peter Billingsley, who memorably played the Red Ryder-wanting Ralphie in the 1983 holiday classic, popped in to play Ming the elf. It's an uncredited role, but between the glasses and those bright baby blue eyes, Billingsley stands out as an A Christmas Story Easter egg. This marks just one of many Billingsley and Favreau's collaborations. Billingsley has been a producer on several of Favreau's film and television projects.

7. Jon Favreau played multiple parts in Elf.

Alan Markfield, New Line Productions

As a writer/director/actor, Favreau has often appeared in his own films. He fronted Made with friend Vince Vaughn, and later found a sweet supporting role for himself in Iron Man. You may have picked him out as the doctor in Elf, but on the DVD commentary, Favreau revealed he also tapped in to his inner narwhal and provided the voices for some of the stop-animation critters who see Buddy off from the North Pole. He also voiced the rabid raccoon Buddy encounters.

8. Baby buddy was fired.

To play the bubbly baby version of the titular elf, Favreau had initially cast twin boys whose blonde curly hair made them great little doubles for the mop-topped Ferrell. However, the production ran into a problem when the boys couldn't perform. Instead of smiling and crawling as needed, they cried relentlessly. To replace them, brunette triplet girls were brought in, who were far perkier and more playful, and thereby ready for their close-ups.

9. Buddy was bullied in an early version.

In first drafts of Berenbaum's Elf script, Buddy's decision to seek out his dad was in part because he was being hassled by the actual elves for being different. Favreau pushed to take out this element. He preferred to keep the North Pole characters warm, even when Buddy bugs them. In the DVD commentary, Favreau offers, “It explained why Buddy was doing all these good things in New York if he grew up in a world where everybody was so sweet even when he’s obviously screwing everything up and doesn’t fit in at all.”

10. Elf hockey hit the cutting room floor.

Poor Buddy accidentally wreaks all kinds of havoc on his elf community because of his ungainly size. One such scene of his well-meaning mayhem featured Buddy playing hockey on a frozen pond. The friendly game becomes unintentionally violent when the too-big Buddy takes to the ice. Though it was shot, it ended up being chopped from the finished film.

11. Elf was shot on location in New York when it counted.

Like many productions, this one took advantage of the financial benefits of filming in Canada, and much of Elf was shot in sound stages in Vancouver. However, when Buddy comes to New York, it was important to Favreau to shoot on location whenever possible. This includes all the Manhattan exteriors, as well as scenes shot at Rockefeller Center, Central Park, and Central Park West, where Buddy's dad lives.

12. Some of Elf’s sets were built in a horror factory.

Okay, technically it was an abandoned mental hospital, where the production team constructed the interior sets for Walter's Central Park West apartment, Gimbels's lavish toy department, and that grim prison cell. The facility is called Riverview Hospital, and it has played host to a long list of film and television productions, including The X-Files, Final Destination 2, Jennifer's Body, and See No Evil 2.

13. Macy's stood in for Gimbels.

The sprawling department store that takes up a whole block in Manhattan was digitally altered to transform into Elf's Gimbels. A bit awkward: Gimbels was once a real department store, and a noted rival of Macy's. Though immortalized here and in the 1947 classic Miracle on 34th Street, the department store closed its doors in 1987, its 100th year of operation.

14. Will Ferrell broke James Caan.

Warner Home Video

The Academy Award-nominated star of The Godfather was hired to play Walter in part because Favreau wanted a stern persona to play against Ferrell's giddy Buddy, and Caan took the comedy of Elf seriously. He knew it was crucial for Walter to be annoyed—never amused—by his supposed son's antics. But when it came to the blood test scene where Buddy bellows when pricked by a needle, Caan cracked. Watch closely and you'll see he turns away from the camera so as not to ruin the take.

15. The studio didn't get a joke from the mailroom sequence.

This was the last set piece shot for Elf, and one that filmmakers were wavering on from its conception late in production. Grizzled Mark Acheson's casting as Buddy's drinking buddy concerned execs because of the line, "I'm 26 years old." The studio noted the actor does not look 26, to which Favreau—who had previously cast Acheson in a small role that had been cut before production—responded that this disconnect was part of the joke.

16. Will Ferrell went method with those jack-in-the-boxes.

In the scene where Buddy suffers as a toy tester, he's subjected to popping open an endless stream of menacing jack-in-the-boxes. The anxiety etched on Ferrell's face in these scenes is real. Rather than standard jack-in-the-boxes that would pop at the song's end, these were remote controlled by Favreau, who purposely manipulated their timing to toy with his star and get authentic reactions.

17. Will Ferrell frolicked all over New York City in character.

The final day of Elf's New York shooting was pared down from a massive crew to just three people: its star, its director, and one cameraman. Together, this trio traveled around the city, looking for mischief for Buddy to get into with random passersby turned background extras. This included him leapfrogging across a pedestrian walk, happily accepting flyers, and getting his shoes shined, all of which made it into the movie's cheerful montage.

18. That epic burp was real, but overdubbed.

Though uncredited, that lengthy belch came not from Ferrell, but from noted voice actor Maurice LaMarche, who might be best known for Brain of Pinky and the Brain. LaMarche shared his secret to such an impressive burp with The A.V. Club, saying, "I’ve always been able to do this weird effect, where I turn my tongue, not inside out, but almost. I create a huge echo chamber with my tongue and my cheeks, and by doing a deep, almost Tuvan rasp in my throat, and bouncing it around off this echo chamber, I create something that sounds very much like a sustained deep burp."

19. Elf made its star stick.

In the movie, Buddy is happy to gobble down an endless supply of sweets, including maple syrup-coated spaghetti and cotton balls made of cotton candy. But this sugary diet played havoc on Ferrell, who told About Entertainment, "That was tough. I ingested a lot of sugar in this movie and I didn't get a lot of sleep. I constantly stayed up. But anything for the movie, I'm there. If it takes eating a lot of maple syrup, then I will—if that's what the job calls for."

20. Will Ferrell refuses to make Elf 2.

Though the comedian reprised the role of Ron Burgundy for Anchorman 2: The Legend Continues and returned as Mugatu in Zoolander 2, he flat out rejected the possibility of bringing back Buddy, even after being offered a reported $29 million. In December of 2013, he told USA TODAY, "I just think it would look slightly pathetic if I tried to squeeze back in the elf tights: Buddy the middle-aged elf."

21. Elf became a hit Broadway musical.

From November 2010 to January 2011, Elf the musical ran on Broadway, boasting songs like "World's Greatest Dad," "Nobody Cares About Santa," and "The Story of Buddy The Elf." This run was a huge success, taking in more than $1.4 million in one week, a record for the Al Hirschfield Theater where it debuted. Plus, The New York Times called it, "A splashy, peppy, sugar-sprinkled holiday entertainment." A revival hit in time for Christmas 2012, and national tours have been recurring.