Since Election Day, President-elect Barack Obama and his team have focused on the transition of power, appointing Cabinet officers and key staff in preparation for the first day of the Obama administration.
But perhaps the trickiest part of that transition will occur today behind the scenes with the physical changing of the guard -- the frantic five-hour period in which the Bush family moves out of the White House and the Obama family moves in.
Former White House usher Gary Walters describes the move in and out of the 132-room mansion as "a very well organized ballet choreography."
"The concept is when [the Obamas] walk in after the reviewing stand that they walk into their new home. Their clothes are in the closets, their favorite foods are in the pantry, the furniture that they have designated to be in certain locations is there," said Walters, who has worked on five presidential move-ins.
Brad Blakeman, a former deputy assistant to President Bush and gatekeeper of the president's schedule in 2001 called it a "military precision operation because you are working against the clock.
"Within the six hours that the parade and swearing-in take place, the White House and West Wing will be totally transformed to receive the new president and his family," Blakeman said.
The Obama family will make the short drive across Pennsylvania Avenue from Blair House, where they are staying, and arrive at the White House around 10:30 a.m.
President Bush and first lady Laura Bush will greet the Obamas at the North Portico entrance and escort them inside to have coffee with the family and some senior staff. When it's time to head to Capitol Hill for the swearing-in, the president and president-elect ride together, alone, in the presidential limo while the first lady and Michelle Obama ride in a separate car behind them.
Once those limos leave the White House grounds, the clock starts ticking.
At about the time that they leave, moving vans filled with the Obamas' possessions brought from Chicago will line up at the Southwest Gate to the White House. The Obamas are responsible for getting their things to this point, but once the trucks reach the White House door, the residence staff takes over for privacy and security reasons.
When the Obamas and Bushes finish their coffee and their motorcade heads for the inaugural ceremony about 11 a.m., the trucks will be waved onto the grounds, and the race against time begins.
The rooms will be stripped of whatever belonged to the Bushes and where necessary, will be repainted, and the Obamas' belongings and furniture will be installed. The movers will be keeping an eye on the clock, because they only have until the last marching band in the inauguration parade passes the reviewing stand before the Obamas walk into their new home, sometime between 4 p.m. and 6 p.m.
Walters said he had a team of about 95 people working nonstop on Inauguration Day to make sure the transition is smooth and complete.