Because he wanted to tie the score!
or
It takes two. One to change the bulb, and the other to kick the switch.
or
The price of bacon would go up.
or
Stinker Bell.
or
One; she designs the bulb to crawl up the wall, unscrew the old one, and screw itself in.
or
Time is fun when you're having flies
or
A garbage truck.
or