He was in shock for a week.
or
It takes two. One to change the bulb, and the other to kick the switch.
or
Billllyuns and billllyuns. Light bulbs are part of the interstellar "goo" that pervades our universe; they are star stuff.
or
Because pepper makes them sneeze
or
Because they only know their ABCs "Anybody But Clinton".
or
It left its tracks.
or