Factual error: When Howard is running after the bouncy ball he is on the second floor of the Mall of America, however, you see him run through the LEGO store which is located on the lowest floor of the Mall of America, which is impossible if he was on the second floor before.
Factual error: When Howie's (Arnie) vehicle breaks down, he's on a landmark bridge in Minneapolis, crossing the Mississippi River at Nicollet Island. He's at essentially Zero Hennepin Avenue, Minneapolis, as the river is the dividing line between East and West Hennepin. He pushes the car off the end of the bridge and rolls to a stop at a diner. This is the landmark Mickey's Diner in downtown Saint Paul, some ten miles away, the one located at 36 Seventh Street West. Howie should have looked even more exhausted than he appears in the film.
Factual error: When Howard runs into Ted and the reindeer, the reindeer's antlers are still in velvet. Velvet is shed in August, at least four months before the Christmas Eve setting.
Factual error: We see Jamie at his karate graduation as a yellow belt. In the scene where his dad apologizes for missing it, he picks up Jamie's new belt, which is purple. Although the order of belt ranks varies by discipline and by dojo, it is highly unlikely that any sensei would have yellow belt (which is almost always the second level) followed by purple (sometimes as low as the fourth ranking, but more often up to the seventh or eighth rank).
Answer: "Russian Dance" from the ballet "The Nutcracker" by Pyotr Tchaikovsky.
Michael Albert