In his first class with Dana, Nick suggests that "the default editor in Ubuntu should be changed from vi to emacs". The default editor in Ubuntu is, and was at the time of release of the film, Nano, not vi.
When Nick and Billy are trying to make their sale in the beginning of the movie they mention that Skylar (Bob's daughter) is an ace on the pommel horse. Bob also shows a picture of his daughter on the pommel horse. Pommel horse is not a women's gymnastics event at all. At any level. So while they girls may have played on it at practice it is highly unlikely that she would be known for that event.
During the Quidditch game, Lyle says in case of dementor attack, use a Patronus charm and he recommends "the stag." In the Harry Potter universe, the shape Patronus takes is unique to each user and reflects their personality. Therefore you cannot choose what form it takes upon someone else's recommendation.
The scene at the north end of the Golden Gate Bridge after the strip club is supposed to be the "morning after". But, traffic on the Golden Gate Bridge (heavy northbound) and the sunlight coming off the actors at Vista Point (from the west) would indicate the scene was filmed in the evening.
When Billy and Nick first arrive at Google, and leave their taxi, Nick has his garment bag slung over his shoulder, while Billy has no visible luggage, clothing or any of the necessities for a several-week stay at Google's headquarters.
In one of the exterior shots, the Bank of America Plaza (a famous skyscraper in Atlanta) is visible. This is especially notable because there are no skyscrapers at all in Mountain View, where the movie is set.