The Social Network (2010)

Factual error: The British character Mr. Kenwright claims his daughter is "majoring in French Literature" at Cambridge University in England, but this is an American expression. English universities do not use the major/minor system; instead, students "study" or "read" their subject of specialization (e.g. "she's reading French Literature at Cambridge").

Factual error: The head of Harvard's office is described as one hundred years older than the country dating it as 1676. When the twins leave they break a doorknob and it is given back with the line "here's your 335 year old doorknob" which would place the action in 2011. In fact it's 2004/5.

Revealing mistake: When Mark gets a nasty note from a Harvard classmate and storms out of a computer class, a directory sign saying "USC College of Letters, Arts & Sciences" (ie. University of Southern California, not Harvard) can easily be seen on the hallway wall through the door as he opens it and walks out.