The boys have a standard lamp on the roof. After the eggs have flown the lamp moves from one side of the air conditioning unit(?) to the other.
The car that Hal is trying to catch is a different car in each scene. Three different years of the Chevrolet Chevelle; 1968,1969, and 1971.
The episode takes place after Halloween but the calendar still says September 2000. However, the calendar changes between September and October 2000 between shots.
Dabney reacts before the water balloon hits his head.
Hal & Lois pull up outside the speeder's house. Hal is not wearing a seat so as to facilitate a rapid exit of the car. This, despite sitting next to the biggest safety/control freak (Lois) in the country.