In the flashback scene, while Toby is talking to Josh about the quintet playing in the lobby, he mentions how for the last two Christmases, he has been accused of having no Christmas spirit around the White House and that he's decided to be different this year. The Bartlet Administration has only been in office since January of the previous year, so they only would have been in the White House for one Christmas so far.
(at around 15 mins) President Bartlet says, "When I was in tenth grade, me and my friends took my father's Country Squire out on a joyride to Vermont." He should have said, "...my friends and I..." A man of Bartlet's education should not have made such an elementary mistake in English grammar.