This year’s official White House holiday gingerbread house is gray. But don’t panic — it wasn’t recycled from the deep freeze of White House Christmases past.

The 300-pound replica of the presidential mansion, made for the first time of rye-, wheat- and white-flour gingerbread, replicates the original sandstone used in the building of the White House. “I went to the first lady’s office to present my idea, and they liked it,” says Bill Yosses, White House executive pastry chef. “We made it to look like it did when it was built with stone from Aquia, Virginia, before they painted it white in 1798.”

First lady Michelle Obama welcomed military families at the annual unveiling of glittering holiday decorations that opens the season of entertaining at the White House. More than 90,000 people are expected to visit the public rooms during this holiday season for tours, receptions and dinners. The year’s theme — drum roll, please — is “Joy to All,” and in the execution, the Obamas use some things old and some things new, which has been a hallmark of their White House holidays. “Joy” joins the Obamas’ previous official themes in White House holiday history: 2009’s “Reflect, Rejoice, Renew” (trees trimmed in dried root materials from the White House garden); 2010’s “Simple Gifts” (wreaths of recycled newspapers); and last year’s “Shine, Give, Share” (recycled aluminum trees) .

Speaking of history, there’s a lot of it on view hanging on the 54 live Christmas trees and the many mantels, tables and windows that have been beautified by 85 volunteers during a five-day decor-a-thon. More than 60 percent of the ornaments displayed are repurposed; others were commissioned for this year’s festivities. On the Blue Room’s 18-foot-6-inch Fraser fir, known as the official White House Christmas tree, dangle ornaments decorated by children of military families who live on bases around the world.

First lady Jacqueline Kennedy is credited with selecting the first White House holiday theme and starting 50 years of presidential traditions of ribbons and bows, lamb chops and eggnog. And don’t forget all those White House pets that are honored at the holidays, including Laura Bush’s Scottish terrier, Barney, who starred in his own series of “Barney Cam” holiday videos, and the Obamas’ Portuguese water dog Bo, who has been depicted made out of pipe cleaners and had holiday cookies made in his likeness. New for 2012: “Boflakes,” large round snowflakes featuring the popular pet. Visiting children will be given bookmarks with a checklist of eight rooms with hidden Boflakes and challenged to find them all.

This year, Obama chose to honor the first ladies of the past five decades with four trees laden with a collection of iconic ornaments, some unearthed from White House storage, others representing the legacy of those who came before. Those are Pat Nixon’s original large foam ornaments, covered in faded turquoise velvet and accented with pearls and gold ribbon (so 1970s). The handblown glass peanuts? They were added to the collection to recall Jimmy and Rosalynn Carter.

White House chief florist Laura Dowling worked with Obama to add some unusual pops of color, such as coral and plum, to the decorations and to find new ways to reuse past decorations. “The combination of new, handmade designs along with repurposed ornaments brings a fresh look to the rooms,” Dowling said.

A few trendy touches spotted: vintage spoons used to decorate the backs of chairs in the China Room and ornaments made of red, white and blue zippers on the East Landing, where a large tree pays tribute to the members of the U.S. armed forces and their families.

The part of this annual ritual that Obama seems to enjoy the most is hanging out with the children of military families. “It’s a cool house. I like it,” she told them in a speech in the East Room. “You guys look gorgeous and handsome today and very clean. And we’re going to try and change that, because we’re going to have sugar and glue and stuff like that.”

Obama, dressed in a gold lurex Michael Kors jacket and pencil skirt that she repurposed from her own closet, then led the kids into the normally staid State Dining Room to create holiday crafts. Under the watchful eye of Abraham Lincoln, youngsters heaped glitter glue onto pomegranate ornaments and dipped candied beets, celery and fennel onto White House honey tea lollipops, making souvenirs to take home. “Try not to glue and lick at the same time,” Obama cautioned them. “Everything is not edible.”

At one point, a little girl in a red velvet party dress who was trying to complete her Boflake ornament started shivering. “Are you cold?” Obama asked. The girl nodded. Soon she was getting a big hug from the first lady.

Just part of the warmth of the holiday season, White House-style.