I was told of this second hand by someone who had heard about it on NPR. Rumsfeld's words presented as poetry.
This was my favorite:
The UnknownIt has also been set to music.
As we know,
There are known knowns.
There are things we know we know.
We also know
There are known unknowns.
That is to say
We know there are some things
We do not know.
But there are also unknown unknowns,
The ones we don't know
We don't know.
Department of Defense news briefing
Feb. 12, 2002
You can buy a CD of his words to music at the above link. Too bad I already had my birthday.