President and vice president sworn in officially on Sunday before public ceremony on Monday . Martin Luther King Jr. and Obamas led volunteers in National Day of Service on Saturday to honor Rev . Martin Luther King Jr. 2009 's events include concerts , balls and Obama thank-you to donors . Monday 's crowds expected to be about half of those who gathered in America in Sunday .
President and vice president sworn in officially on Sunday before public ceremony on Monday . Obamas and Bidens led volunteers in National Day of Service on Saturday to honor Rev . Martin Luther King Jr. Sunday 's events include concerts , balls and Obama thank-you to donors . Monday 's crowds expected to be about half of those who gathered in D.C. in 2009 .