Before the fun stuff, somber notes.
PHOTOS: White House Christmas Decorations
The tree is aglow with gold-rimmed white stars honoring individual dead, and next to it a large monitor flashes their pictures, short biographies and messages from the families left behind.
One is Pfc. Kristofor Stonesifer, 28, of Missoula, Mont., an Army Ranger killed the night the U.S. invaded Afghanistan in 2001.
His mother, Ruth Stonesifer of suburban Philadelphia, helped trim the tree to remember her son -- in her words, "a vegan, vegetarian philosophy major" who had been an ROTC student at the University of Montana.
The largest of the White House trees -- an 18 1/2- foot balsam fir from Wisconsin -- honors "Blue Star Families" with a member in the armed forces.
Standing tall in the Blue Room, the majestic tree carries a collision of medals, battle ribbons, brass buttons, old martial photos and even an ornament camouflaged for combat, wearing digitized green.
A small army helped with this year's decorating, with White House personnel joined by 136 volunteers from 37 states. The largest contingents came from Illinois (14) and California and Virginia (12 each).
Room after glorious room, festooned with topiaries, poinsettias, red roses, crystal snowflakes, shimmering stars, silver bells and mile after mile of pine swags and colorful, wired ribbon, they strove for what stylists call the "wow" factor.
And the "bow-wow" factor.
The Obama's Portuguese water dog, Bo, is featured in almost every room, appearing in fabric, buttons or candy. One sculpture took 35 yards of black and white felt; another, 318 buttons; and the sweetest of all, 1,911 pieces of black licorice and a dozen marshmallows. Higher in calories -- and crowd appeal -- is the 400-pound White House gingerbread house that features white chocolate instead of sandstone as its exterior. It took two months and many more hands to concoct the nearly two-foot confection, said pastry chief Bill Yosses.
The creation, he joked, required "all of the food groups: marzipan, macaroons and chocolate."
He showed his piece de resistance off on Wednesday to military families and children, the earliest guests -- and wouldn't you know it, who should steal the show?
"The real Bo!" one child squealed as the pet, wearing a red leash, padded into the State Dining Room.
Bo even has planted a paw print near where the rest of the Obamas have signed their 2011 holiday card, an artist's rendering of the White House library, all spruced up for Christmas and its fireplace roaring.
Its message: "From our family to yours, may your holidays shine with the light of the season."
First Lady Michelle Obama signed off on this year's holiday theme, which officials said celebrates the "countless ways we can lift up those around us, put our best self forward in the spirit of the season, spend time with friends and family, celebrate the joy of giving to others and share our blessings with all."