Abominable! [A Bomb In a Bull]
or
I better not tell you, it might spread.
or
Because it would fall over if it lifted the other one.
or
The question is irrelevant, since you couldn't find the dolls even if you knew how many. (Note: Well, this was a good joke in 1983-84. . . .)
or
A guy who has never been hit with a dictionary.
or
We'll see about that."
or
Two. One to take notes while the other screws it into the faucet.
or