In 1888, when the Statue of Liberty was still shiny and copper-colored, two German-speaking immigrants on the Lower East Side, perhaps inspired by that French gift, borrowed the French word for delicateness (délicatesse) to describe their new shop of fine German fare.

The result was the Iceland brothers' delicatessen, which was bought the following year by three entrepreneurs by the name of Katz, Mackstein and Tarowsky. It eventually became known as Katz's, which bills itself as the nation's oldest deli and is in the throes of celebrating its 125th anniversary.

Jake Dell, who curated an exhibit of work inspired by Katz's Deli. Cassandra Giraldo for The Wall Street Journal

The latest celebration is a pop-up gallery of Katz's-inspired art. The curator is Jake Dell, the 26-year-old fifth-generation Katz whose business card lists his job title as "top dog." The gallery opened Tuesday night to the public with free beers and a line around the block. It will feature rotations of art for the next three months, said Mr. Dell.

Highlights of the current kitchen kitsch include a drawing of a rabbi made of tongues and a series of Katz-related etchings carved into vinyl records of, say, the soundtrack to the musical "Cats" or Cat Stevens's greatest hits.

Plastering the wall in huge letters like a Tracey Emin artwork was the most famous phrase ever uttered in the restaurant: "I'll Have What She's Having"—stage-whispered in the iconic 1989 romantic comedy "When Harry Met Sally" after Meg Ryan fakes a 68-second, 15-yes orgasm for Billy Crystal.

Although that Hollywood moment wasn't the high point for Alan Dell, Jake's 66-year-old father, who began working in the deli shortly before the movie's release. "For me, it was all about every time Soupy Sales walked in the door," he said, of the longtime local children's show host he described as like Mister Rogers "only dirtier."

But he added that he also loved that the contract to kill Frank Sinatra's character in the 1977 film "Contract on Cherry Street" was made in Katz's meat locker.

"The image of a deli is so changed nationally by a place like Katz's," said Andrés Valencia, a 32-year-old advertising account director from Williamsburg, as he admired the art. "It ruins delis for the rest of the country."

In addition to the art, the gallery showed a Katz-themed pair of Nike Air Jordans, a Katz-themed iPod, apparel by local outfitter Alife and an autobiography of the restaurant.

"It makes it young again," cheered Margie Ashcroft, a 27-year-old writer from the Upper West Side.

Rich Tu, a 31-year-old artist from Bushwick who contributed "Army Brat" (as in bratwurst: it's a painting of a salami wearing a camouflage helmet and the text "send a salami to your boy in the Army," a World War II slogan of Katz's), tucked a cigarette behind his leopard-print cap and explained his work: "The last time I was in Katz's I got arrested for putting stickers all over the neighborhood and that poster in the shop was the last thing I Instagrammed, so it was burned in my memory."

Marveling at the shoulder-to-shoulder crowd of mostly hyper-cool 20 somethings, Franklin Veras, a 30-year-old radiology student who has worked at Katz's since he was 14 and lives a few blocks away from the deli, beamed: "It's super New York. It's super neighborhood. It's super family. It's super everything, man."

Many of the attendants said they had rarely—if ever—eaten at the deli itself. "It's a tourist spot, but it's great," said Luther Young, a 25-year-old graphic designer from Harlem. "It's a New York thing that New Yorkers don't do, like going to the Statue of Liberty."