Conan O’Brien did little to manage expectations as he kicked off Sunday evening’s “30 Rock” reunion, a one-night-only benefit at Radio City Music Hall to celebrate the beloved sitcom’s 20th anniversary.

“Welcome to the greatest night in the history of entertainment!” he said from the stage to raucous applause. “I’m Conan O’Brien, and I’m known to exaggerate.”

His comments didn’t seem hyperbolic to the 5,000 rowdy fans in the audience, who spent a pretty penny and braved a rainstorm for a chance to witness the live, never-to-be-televised event. Cheers from the crowd were near-deafening as O’Brien introduced the cast — Tina Fey, Alec Baldwin, Tracy Morgan and Jane Krakowski — and they kept up the enthusiasm for surprise guests like Jon Hamm, Tom Hanks, Lin-Manuel Miranda, Will Forte and Brian Williams.

“What you will see tonight is, in “30 Rock” fashion, an overly ambitious grab bag of nonsense,” Fey said. Created by Fey, “30 Rock,” which ran for seven seasons on NBC from 2006-2013, takes place behind the scenes of a fictional “Saturday Night Live”-esque sketch comedy show called “TGS With Tracy Jordan.” Fey plays head writer Liz Lemon, Baldwin portrays NBC boss Jack Donaghy and Krakowski and Morgan star as cast members Jenna Maroney and Tracey Jordan.

The cast reunion doubled as a charity fundraiser for the Boys and Girls Club of Harlem, an organization they wanted to honor for two specific reasons. “We chose the Boys and Girls of Harlem because they are a great New York institution,” Fey said. “But also because we figured we kind of owed them something because of how much Tracy Jordan struggled to shoot the commercial he did.” (In one memorable episode from Season 5, Tracy couldn’t remember his lines as he filmed a public service announcement for the Boys & Girls Clubs of America.)

Fey revealed that Jack McBrayer was the one to suggest a 20th anniversary reunion. “He probably meant a cast dinner. But I’m not a good listener, so here we are,” Fey said. “I wanted to celebrate at Radio City because I like to feel tiny.”

She designed the evening to be “more than just a Q&A,” stuffing the 90-minute event with elaborate musical numbers, game show sketches and other “30 Rock”-themed skits.

“No one has ever seen this show before, including us, because we have not rehearsed it,” Fey said. “But one thing I can promise you, from the bottom of my heart, we will have microphone problems.”

If you couldn’t “go to there,” as Liz Lemon would say, Variety has compiled the best moments from the night:

“30 Rock” had no shortage of A-list guest stars, from Carrie Fisher (as fictional comedy writer Rosemary Howard) to Steve Martin (as Jack’s neurotic friend Gavin Volure) to Oprah Winfrey (as herself). “It was pretty wild,” said Judah Friedlander, who played “TGS” writer Frank Rossitano. “You never knew who would show up. One week it was Al Gore, and the next it could be Queen Latifah.” Katrina Bowden, who portrayed Liz’s beautiful assistant Cerie, asked: “Wait, are those real people who lived?”

But only one bold-faced name could win the coveted “best guest star” prize, which went to Elaine Stritch as Jack’s overbearing mother Colleen Donaghy. She was (posthumously) nominated against Marcella Roy as young Liz Lemon, Sherri Shephard as Tracy’s wife Angie Jordan and Kelsey Grammer as his heist-wielding alter ego “Frajer.”

“Unfortunately, Elaine can’t be here tonight to accept her award because she’s dead,” Bowden deadpanned. (Strich died in 2014 at age 89.) “So here to accept on her behalf is two-time Academy Award winner Tom Hanks.”

Hanks was apparently tricked into attending the evening while he was one block up, near 30 Rockefeller Plaza. “I was on my way to dinner at the Rainbow Room,” Hanks said. “I eat there every night to avoid Mamdani’s pied-à-terre tax.”

“30 Rock” is famous for predicting a bunch of stuff that proved to be bizarrely accurate. “Even though we were exhausted and writing absurdist nonsense, so much of what we wrote actually came true,” the show’s writers said from the stage. Highlights in a montage of prescient jokes include Jenna’s “free Lyle Menendez” tattoo (the brothers were recently granted an early parole hearing) and Tracy’s call with someone pretending to be Bill Cosby — “You’ve got a lot of nerve getting on the phone with me after what you did to my Aunt Paulette!” — way before the comedian was accused of drugging and sexually assaulting women. Then there was Jenna’s weight-gaining role in the fictional “Mystic Pizza: The Musical” (which now exists and began a national tour this fall) and the iconic show-within-a-show “MILF Island,” which paved the way for the very real HBO Max reality dating series “FBoy Island.”

McBrayer put Fey and Morgan’s memories to the test, feeding them niche quotes from the show to see if they could remember the wacky things their characters said over the course of seven seasons. They started strong; Fey knew the reason there “ain’t no party like a Liz Lemon party” because “a Liz Lemon party is mandatory.” And Morgan remembered the seminal “advice I wish I woulda got when I was your age” which was to “live every week like it’s Shark Week.”

And then things took a turn. Fey was stumped by a clip of Liz, dressed as Princess Leia from “Star Wars” to try to get out of jury duty. “Because I can read minds?” Fey guessed. (Her actual line was “Because I’m a hologram.”) But she rebounded with her character’s memory of participating in the “Big Sister” program. (“That little girl taught me how to use a tampon.”)

When Morgan couldn’t think of the punchline to “What is this, horseville?” he turned to the audience to supply the answer. Everyone shouted: “Because I’m surrounded by naysayers. Wordplay!” Morgan couldn’t recall other Tracy-isms, like, “I don’t get why people like brunch. What’s the benefit of combining breakdancing and lunch?” and “I was just thinking about how weird it is that we eat birds.” But he had a good excuse.

“I’m supposed to remember that?” Morgan said. “You gotta give me a break. I got hit by a truck!”

Chris Parnell’s wacky doctor Leo Spaceman, who gets promoted to Surgeon General of the United States at the end of the series, was on hand to “clear up any confusion about our official health recommendations.” A sampling of his frequently asked questions: “Do vaccines cause autism? Or, does autism cause billionaires?” (“Either way, you’re in trouble, fam.”) “Is it safe to eat lettuce yet?” (“Nope, it never was. Stick to the paleo food groups: Beef, meat, and Zyns.”) “Can I give my spouse a GLP-1 without them knowing?” (“Now, any doctor will tell you: If you don’t know the law, you can’t break it.”) That should clear a few things up!

Since the series went off the air in 2013, “30 Rock” guest star and former “NBC Nightly News” anchor Brian Williams admitted he’s been missing Jack Donaghy’s pithy advice and commentary on the state of the world. One of the night’s sharpest sketches  — introduced by Williams — involved Jack responding to major news events of the last 13 years.

— In 2014, Jack’s assistant Jonathan (Maulik Pancholy) told his boss that his emails were leaked in the infamous Sony hack. “The one where I tried to get Tracy in drag in the female ‘Ghostbusters’?” Jack asks, to which Jonathan replies, “No, I never sent that one. It’s the one where you offer to give Jenna to Kim Jong Un if it would help.”

— In 2017, Kenneth, the eager page played by McBrayer, reveals he was “#MeToo’d by a lady on the camera crew.” He elaborates, saying, “She asked me what my ideal last meal would be, and I said chickpeas and Mountain Dew.’ She said, ‘Me too!’ And then we high-fived so hard, my pants fell down.”

— In 2021, Jack shamed the insurrectionists who stormed the capitol on Jan. 6. “When I defecated on Nancy Pelosi’s desk,” he said, “I looked in her straight in the eye like a man.”

— In 2023, Jonathan celebrated a box office rebound — “Sir, ‘Barbie’ and ‘Oppenheimer’ were a huge success. The movie business is back! — and Jack retorts: “And more importantly, now when you Google “Barbenheimer,” that’s what comes up, and not Cody Barbenheimer, the young man who mysteriously drowned in Lindsey Graham’s bathtub over Memorial Day weekend.”

Fresh off her run in “Oh, Mary!” on Broadway, Krakowski wowed the room by performing several of the attention-seeking Maroney’s greatest hits. Wearing a sparkly silver dress and flanked by dancers in page uniforms, she opened with “That’s Her,” the opening theme song from “The Girlie Show” and masterfully pivoted into the feminist anthem “Muffin Top” before transitioning to Jackie Jormp-Jomp’s classic “Chunk of My Lung,” a parody of Janis Joplin’s “Piece of my Heart.” (Jenna was cast to play the music icon in an unlicensed biopic that never got off the ground.)

The already giddy crowd erupted when Krakowski was joined by John McEnroe to belt the “Sunday Night Football”-inspired “Tennis Night in America” and later by Forte, dressed as an angel in character as Jenna’s beau Paul L’astnamé, for a duet of the Christmas carol “O Holy Night.” Marceline Hugot, who plays Kathy Geiss, the mute daughter of GE’s boss Don Geiss, made a brief but thrilling appearance on trumpet.