David Rice Atchison (August 11, 1807-1886) was a mid-19th century Senator from Missouri who was President of the United States for one day: Sunday, March 4, 1849, between the expiration of James Polk's term at noon on Sunday and the official oath of office taken by Zachary Taylor on Monday. The law at that time specified that the President was to be sworn in on March 4th, but President-elect Taylor refused to be sworn in on the Sabbath (Sunday). Atchison had been elected President Pro Tempore of the Senate a couple of days previously and was therefore technically third in line of succession behind the President and Vice President. Since neither office was held by a person on that day, he was technically the President of the United States for that period.
When asked what he did on this day, he commented "I went to bed. There had been two or three busy nights finishing up the work of the Senate, and I slept most of that Sunday." 
Born in Frogtown (now named Kirklevington), Fayette County, Kentucky, Atchison was appointed to the United States Senate to replace a Missouri Senator that had just died. He held this office from 1843 to 1855. He became the first senator from western Missouri and at age 36 the youngest Missourian at that time to enter the U.S. Senate. He also was U.S. Vice President from April 18 1853, until December 4 1854, by right of succession upon the death of President Franklin Pierce's vice president, William R. King. He is buried in his home of Plattsburg, Missouri, where a statue honors him in front of the Clinton County Courthouse.