It takes two. One to change the bulb, and the other to kick the switch.
or
Because he was bald!
or
Climb up a tree and act like a nut
or
Five. One to screw it in and four to tell him how bitchin' he looked doing it.
or
When it came time to pay, the skunk didn't have a scent, the deer didn't have a buck so they put the meal on the duck's bill.
or