Continuity mistake: At the end of the movie, Kevin wants to meet "the L girl" at their stop at 7pm. While Kevin is waiting, the camera goes to the clock. First it says 7pm. After waiting a few minutes, it says 7:10pm. Then when Kevin finally gets to Abby, the clock in the background only says 6:55pm.
Plot hole: Kevin is waiting at the train station for "the L-girl", and she sends a paper plane down to Kevin to get his attention. By this time the reporters have lost interest, and are turning away. Kevin looks up and starts to walk towards Abby, and the TV cameras start to run up to Abby to get a shot of her. Only problem is, How did they know what she looked like? Kevin is the only one who knows that she is the "real" L-girl.
Continuity mistake: When Kevin and his roommates are playing baseball and having a barbecue on the field, Lance's hair is brown with blond streaks. In the next scene his hair is black again.
Continuity mistake: In the last scene with Kevin and Abby she is wearing a denim jacket. When you see the newspaper picture for the scene she is wearing a leather jacket.