BROOKLYN - Thousands of people lined up Saturday outside the Brooklyn YMCA Armory to receive food, clothes and toys during the annual Christmas Day celebration. More than 400 volunteers and organizers expected about 2,500 people to come out for the 21st annual Christmas Day event, which was held at the YMCA on 15th Street for the first time."I have a lot of things in my life that I'm thankful for, and I'm glad that I can come here and give some of that to them," says volunteer Francisco Rosado.This year's Christmas Day celebration attracted people from across the tri-state area, who turned out in Park Slope to enjoy a warm meal with friends.Children and teens also got to pick out their presents from among the toys that were donated, while adults received jackets, hats, scarves and other essentials.