On Sunday mornings, when I was a kid, we'd wake up and have bagels and lox that my grandfather would bring over to our house early in the morning. This family does other stuff on Sunday mornings...
You'll note that Chief Justice Roberts was working from a piece of paper this time, so as to avoid the mistake he made administering the oath incorrectly, from memory, during the official swearing in in 2009. That gaffe led to a "mulligan" swearing in the following day, privately, in the White House.
For the record, today's swearing in is the official start of President Barack Obama's second term under the U.S. Constitution, which specifies, in the 20th Amendment, that "The terms of the President and Vice President shall...then begin" at noon on the 20th day of January. (Prior to the 20th Amendment, Presidents had been sworn in on March 4th.) But, since, this year, January 20th falls on a Sunday, the public swearing in will take place on Monday, January 21st instead, in a massive ceremony outside the U.S. Capitol, as per tradition.
According to an announcement from Sen. Charles Schumer (D-NY), chair of the 2013 Joint Congressional Committee on Inaugural Ceremonies, as cited by USA Today "this is the seventh time in U.S. history that the constitutionally mandated inauguration date has fallen on a Sunday."
"The last time was for President Ronald Reagan's second inauguration in 1985," said Schumer's office. "When this occurs, the public ceremonies traditionally are held on Monday."
Past inaugurations to fall on Sundays, with public ceremonies moved to the following Monday, include James Monroe's 2nd (1821), Zachary Tayor's (1849), Rutherford B. Hayes' (1877), Woodrow Wilson's 2nd (1917), Dwight D. Eisenhower's 2nd (1957) and Ronald Reagan's 2nd (1985).
Schumer's office notes that January 21 "is Martin Luther King Jr. Day. It will be the second time that this federal holiday has coincided with a presidential inauguration. The first was President Bill Clinton's second inauguration on Monday, Jan. 20, 1997."
The timing of this year's ceremonial swearing in makes makes this Photoshopped graphic, widely circulated during Obama's first inaugural, perhaps even more appropriate, even if somewhat less moving four years later...
USA Today also notes that "The law designating the third Monday in January as a federal holiday honoring the Rev. Martin Luther King Jr. was signed into law by President Reagan in 1983. President Reagan's 1985 inauguration fell on the third Monday of January, but the new federal holiday did not become official until 1986."