Towards the beginning of the movie, the Bell Atlantic sticker on the phone receiver is faded, but it eventually turns into a brand new sticker.
The big speech from "Couldn't you find anyone worse? A child molester..." to the bit where Stu is shot was filmed in one take. Colin Farrel did everything and surprised himself and the crew. When he hit the floor, the crew (and the extras) had to contain their applause until the cameras stopped rolling.