Dancing Phone Receiver
While the rookie cop (Angelina Jolie) is sleeping off a 'few-too-many', the phone rings. She picks it up only to discover it is (Denzel Washington). She hangs up the phone, then lifts it and places it face down on the night stand. As the camera pans around, you can see the receiver has somehow flipped over to its back. When another cops arrives, the receiver is again face down, only to flip one more time before the scene is over.
At the end of the movie, notice where Denzel Washington gets his left finger broken, then at the christmas party, the index finger on his right hand is bandaged.