When taping the copier to the underside of the bicycle, the display screen shows on, but it is obviously not plugged in.
When Dwight is hanging from the high-wire, papers are seen to scatter, but they obviously did not come from the copier.
At 24 min in Pam and Dwight are talking on the roof of the building. As Pam walks away you can see her trying to hold back laughter.