Continuity mistake: A group of people are in the copying room taking turns taking pictures of their butts on the copier. When one of them sits on the glass part of the copier, the glass part breaks. When he gets up, it's not broken.
Continuity mistake: When Josh and Tracy are outside, on the top of the building, you can see a wedding ring on Josh's finger as he is looking over the edge of the building. He doesn't have a ring on in any other scene.
