He made an illegal ewe turn.
or
Three skunks fighting over a pickle
First dog: My master calls me Furball. How about you?
Second Dog: My master calls me Sitboy
or
None. There never was any light bulb.
Notes: Probably the only really good light bulb joke of 1984.
or
One minds the train, one trains the mind.
or
Because he wanted sweet dreams.
or
In the neigh-borhood.
or