Even as it celebrates with a gala, the Ars Nova family now faces another challenge as one of its founders confronts A.L.S.In 2002, Jenny and Jon Steingart founded the Off Broadway incubator Ars Nova as a way of honoring Jenny’s brother, Gabriel Wiener, who in 1997 died of a brain aneurysm at the age of 26. Now, as the nonprofit theater is marking its 20th anniversary, the couple is facing another wrenching struggle: Jon has A.L.S., the severe neurological disorder also known as Lou Gehrig’s disease.“Every painful experience in my life — if I have to live through it, I am going to come out on the other side with a lesson and a way to give back in some way,” Jenny Steingart said in a recent interview at their home on the Upper West Side. “Because a loss without some meaning behind it is really hard to live with.”So this anniversary, to be celebrated with a gala on Monday, also finds the Steingarts feeling great satisfaction, having created an institution that — in the wake of the 9/11 attacks — has played a crucial role in the professional development of so many artists.Among those who have worked at Ars Nova are Lin-Manuel Miranda, Thomas Kail, Christopher Jackson and Phillipa Soo of “Hamilton” fame; Bridget Everett, the actress and cabaret performer of the acclaimed HBO series “Somebody Somewhere”; and Dave Malloy, who created “Natasha, Pierre & the Great Comet of 1812” at Ars Nova.More recently, Ars Nova presented Heather Christian’s widely-praised music-theater piece “Oratorio for Living Things,” after being delayed by the pandemic shutdown.“This theater has done the good work of incubating extraordinary artists,” said the “Hamilton” producer Jeffrey Seller, adding that Mimi Lien, the scenic designer for his current Broadway production of “Sweeney Todd” — who won a Tony for “Great Comet” — came out of Ars Nova. “Many people make things,” he added, “but few of them are vital 20 years later.”When Ars Nova offered Everett a creative home, she was performing in karaoke bars. With its support, she developed her brash 2007 solo show, “At Least It’s Pink” at Ars Nova. “I was taken aback by their enthusiasm for me because I wasn’t getting anything anywhere,” Everett said. “I would not have a career if it wasn’t for them seeing something in me.”The improvised rap evening “Freestyle Love Supreme” had its beginning at Ars Nova, which also helped birth the musical “KPOP.”The director Alex Timbers (“Moulin Rouge! The Musical,” “Bloody Bloody Andrew Jackson”) got his start at Ars Nova, with Peter Sinn Nachtrieb’s doomsday comedy “Boom.” “It was the first time I’d been hired professionally to direct and given access to designers I would never have gotten to work with on my own,” he said. “It was not only a gift, but a leap of faith.”The cast of the 2017 Off Broadway production of “KPOP,” which occupied two floors of a building in Hell’s Kitchen.Vincent Tullo for The New York TimesLucas Steele, left, and Denée Benton in the 2016 Broadway production of “Natasha, Pierre & the Great Comet of 1812” at the Imperial Theater.Sara Krulwich/The New York TimesAt the gala, Ars Nova will announce a financial pledge from the Steingarts that will enable a more consistent presentation of comedy in addition to its current variety show, “Showgasm.” Citing, for example, Ars Nova’s “Creation Nation,” a popular live variety program that featured the comedian Billy Eichner, Jon Steingart said comedy — as well as music — taps into “where youth culture is right now.”Jenny Steingart, 55, a Manhattan native, said her parents — Michael A. Wiener, who helped found the Infinity Broadcasting chain of radio stations, and Zena, a music teacher and singer — encouraged her to follow her passion. “‘What are you aligned with?’” she recalled them asking. “‘What is the thing that sparks you?’”Jon, now 55, grew up in Southern California and was a producer of the Broadway show “Julia Sweeney’s ‘God Said “Ha!.”’” They married in 2002 and now have three children, ages 19, 16 and 13.After the death of her brother, who produced recordings of early music, Jenny said she and Jon “let his legacy inspire the creation of new art.”Jenny Steingart and Anthony Veneziale accepted a special Tony Award for “Freestyle Love Supreme” in 2021. Theo Wargo/Getty Images For Tony Awards ProIn the early years, the Steingarts, together with the theater’s founding artistic director, Jason Eagan, were out every night trolling for talent, an approach that continues to this day. “We’re looking at artists with potential,” Eagan said, “rather than artists with résumés.”Ars Nova, which planted its flag on West 54th Street, quickly established itself as a space where artists could take big chances, where “you can say, I want to make an electro pop opera about a slice of ‘War and Peace,’” said Renee Blinkwolt, the company’s producing executive director, referring to “Great Comet,” which won Tony Awards for lighting as well as scenic design. (In 2016, the show’s commercial producers agreed to revise how it credited Ars Nova’s contributions to “Great Comet” in Playbill.)Despite having cemented its status as a staple of the New York theatrical landscape, Ars Nova, which in 2019 opened a second theater at Greenwich House in the Village, remains relatively scrappy, with an annual operating budget of about $4 million and a staff of 14. A ticket subsidy program keeps prices low and this season offered pay-what-you-wish.During the pandemic, no employees were furloughed, thanks in part to the Paycheck Protection Program, which covered about 10 percent of the funds required to keep paying artists and staff.These days, the Steingarts are less involved in running the organization, but they continue to play a strong supporting role. Jon spends most of his time researching his disease — “I don’t quit,” he said — recognizing that he is fortunate to be alive five years after his diagnosis. Sitting in a wheelchair at his kitchen table, Jon also described himself as “pretty even keel about acceptance.”“I’m not a person who, win or lose, spends a lot of time asking why me,” he said.Jenny, however, is a little less accepting, although she is doing her best to keep it together.“I don’t want to be Debbie Downer, and I also don’t want to be Pollyanna,” she said. “It’s really important to me to lean into the gratitude I have and the blessings that have come from even the worst stuff.”Though Ars Nova’s close-knit extended family has had to adjust to the prospect of a future without one of its parents, the artists are trying to do what they’ve always done: stay positive and persevere.“The tragedy of losing her brother and what Jon is going through — it’s the brutality of life,” Everett said. “But I’m really glad that what Ars Nova has given does sustain. Putting people on course and giving them a chance — what better gift is that?” More