At the beginning of the holiday season, bikers roll up to the Papermill Creek Saloon to celebrate the end of their annual fundraiser: truckloads of toys presented to children whose parents are serving time in San Quentin State Prison. The chrome of hundreds of motorcycles line the streets outside the saloon while bikers mill about, play pool in the bar or dine on a hearty meal. “It’s kind of like a family event,” one biker said. “Everybody gets together and rides out there and do what we do.” The saloon is the last stop for this charity drive. For nearly two decades, Bret Hatt, who owns a bike repair shop in Forest Knolls, and his friend Ricky Waters have led a band of bikers in bringing holiday cheer to children with incarcerated parents. “Children of people that get incarcerated get forgotten about a lot,” Mr. Hatt said. “It’s not the kids’ fault, and someone has to do something for them.” Seventy bikers came on the first toy run, in 2000, and more recent years have drawn 300 bikers. Participants ride from Pier 15 in San Francisco to meet children at the Marin Rod and Gun Club to present them with toys, some donated by community members and others by the bikers themselves. John Smith, a Petaluma participant who said he served “a lot of time” in San Quentin, said they have collected two truckloads’ worth in recent years. Roughly 50 children participate each year, and over the years the bikers have built a kinship with them. “A lot of them we’ve known for some years, like [if] their dads are doing life in prison,” Mr. Smith explained, “and they love the shit out of us.” Along the ride, bikers pick up playing cards as part of a poker run. (Poker runs, Mr. Smith explained, are just part of biker culture. “Every run—the Hell’s Angels, the Bity City Riders—they always do a poker run,” he said.) They get cards at Pier 15, at the Rod and Gun Club and at the Papermill Creek Saloon; the person with the highest hand—and the one with the lowest—win prizes. Though Mr. Smith’s own children were born after he was released from prison, he empathizes with incarcerated parents who are unable to provide presents for their kids. “We want to give back to the community and let kids know their Christmas isn’t lost because their dads are gone,” he said. A few years back, Mr. Smith recalled, a number of bicycles had been donated. When a young boy grabbed one before he was supposed to, organizers had taken it away. The young riding enthusiast went to Mr. Smith sobbing, and the biker helped him get his vehicle back. “It just happened that the kid’s name was John-John, and that’s what my friends call me,” said Mr. Smith. “That was my favorite memory—he just hugged me all day.” This year’s toy run will take place on Nov. 24, and anyone interested in donating can bring unwrapped toys to the event on that date or ahead of time to Mr. Hatt’s motorcycle shop at 6956 Sir Francis Drake Blvd., in Forest Knolls.