Gwyneth Paltrow and Chris Martin's 6-year-old daughter Apple rode in Leadline – the division for the show's littlest riders – while Kelly Ripa and Mark Consuelos's 9-year-old Lola rode in some more advanced divisions and jumping classes.
"She really had a lot of fun," the proud dad told PEOPLE at the show on Sunday. Lola and her pony, Dawn's Early Light, scored two second place ribbons, one third and one ninth in their classes.
"I'm in charge of the shoe shining," Conseulos added. "Kelly does the ribbons." Other celeb parents on equine duty in the Hamptons included Matt Lauer and his wife Annette Roque, whose daughter Romy, 6, also competed.
"My daughter did great," Annette reported. "I was a mess, I was sweating! She got a silver ribbon." Added Matt, "Romy loves the sport and she doesn't really care about where she finishes."
In the adult divisions, New York City Mayor Mike Bloomberg's daughter Georgina won $6,500 in one of the biggest classes in the show. Meanwhile, Real Housewives of New York star Kelly Bensimon took a tumble in her class.
"Sometimes I'm really, really good," she told PEOPLE. "And sometimes I'm really, really bad. On Thursday I fell off. I was humiliated but on Sunday last week, I got fourth place."