Following the swearing-in ceremony, President Obama and Vice President Joe Biden will attend the inaugural lunch in the Capitol. The lunch is a tradition dating back to President William McKinley’s first inauguration in 1897, according to the Presidential Inaugural Committee's media guide.
From the guide:
Approximately 200 guests will join the President, Vice President and members of the Joint Congressional Committee on Inaugural Ceremonies at the Luncheon, which will be held in Statuary Hall. A painting by Ferdinand Richard of Niagara Falls, selected by the Chairman of the Inaugural Committee, will serve as a backdrop for the head table. Music will be provided by the University of Rochester Eastman School of Music. At the Luncheon, the President and Vice President will be presented with official gifts from the Congress on behalf of the American people.