Fifty — one to screw in the bulb and 49 to guard him/her.
or
They screw millions of bulbs every day, but when it comes to your bulbs, there's no record.
or
One in 3,000,000 has a chance of becoming a human being.
or
It takes two. One to change the bulb, and the other to kick the switch.
or
I said, "I can't make Tuesdays"
or