I’ve also used the following from the Narnia books, back when I was living in the country. This was, of course, years before the movie.
And now there was no doubt that the trees were really moving - moving in and out through one another as if in a complicated country dance. (‘And I suppose,’ thought Lucy, ‘when trees dance, it must be a very, very country dance indeed.’)
C.S. Lewis
I got it and the below by reading the books in question.
I’ve also been known to use the following on occasion:
“… the times have been, that, when the brains were out, the man would die …” – Macbeth, Act III, Scene IV (William Shakespeare)
just from a cool movie. 
I tend to change mine frequently (although I really like this one a lot, so I think I’ll keep it for a while 
), and I just do a search on an author I like. You can usually find quite a few that way.
I believe I quoted Harpo in my sig once. I think it went something like this: " ".
I just like quotes, and try to remember them. My current one was in a Rolling Stone (magazine) I was reading at the doctor’s office a week or two ago. It’s my second from a Rolling Stone (band member) in the last few months.
My next one, I heard on the radio last weekend:
“I say this as a devout Republican. With the current partisan tension in Congress, if Tom Delay even thinks about doing something like he’s done, he might as well tie a coat rack to his head, glue a white powderpuff to his butt, and run through the woods during deer season.” – PJ O’Rourke
Oh, good. I was afraid that was too subtle.
Mine came from a mnemonic…I was trying to remember what note I started “I wonder what’s keeping my true love tonight” on! Later, it just tickled my fancy, so I kept it.
Redwolf
My current sig line is from a newspaper reporter who wrote an article about a week where tigers made the headlines twice in incongruous situations.
My long time sig line is from a poem by Borges:
The Other Tiger
A tiger comes to mind. The twilight here
Exalts the vast and busy Library
And seems to set the bookshelves back in gloom;
Innocent, ruthless, bloodstained, sleek
It wanders through its forest and its day
Printing a track along the muddy banks
Of sluggish streams whose names it does not know
(In its world there are no names or past
Or time to come, only the vivid now)
And makes its way across wild distances
Sniffing the braided labyrinth of smells
And in the wind picking the smell of dawn
And tantalizing scent of grazing deer;
Among the bamboo’s slanting stripes I glimpse
The tiger’s stripes and sense the bony frame
Under the splendid, quivering cover of skin.
Curving oceans and the planet’s wastes keep us
Apart in vain; from here in a house far off
In South America I dream of you,
Track you, O tiger of the Ganges’ banks.
It strikes me now as evening fills my soul
That the tiger addressed in my poem
Is a shadowy beast, a tiger of symbols
And scraps picked up at random out of books,
A string of labored tropes that have no life,
And not the fated tiger, the deadly jewel
That under sun or stars or changing moon
Goes on in Bengal or Sumatra fulfilling
Its rounds of love and indolence and death.
To the tiger of symbols I hold opposed
The one that’s real, the one whose blood runs hot
As it cuts down a herd of buffaloes,
And that today, this August third, nineteen
Fifty-nine, throws its shadow on the grass;
But by the act of giving it a name,
By trying to fix the limits of its world,
It becomes a fiction not a living beast,
Not a tiger out roaming the wilds of earth.
We’ll hunt for a third tiger now, but like
The others this one too will be a form
Of what I dream, a structure of words, and not
The flesh and one tiger that beyond all myths
Paces the earth. I know these things quite well,
Yet nonetheless some force keeps driving me
In this vague, unreasonable, and ancient quest,
And I go on pursuing through the hours
Another tiger, the beast not found in verse.
– Jorge Luis Borges
Of course, there is my old old sig line that most people know:
William Blake. 1757–1827
TIGER, tiger, burning bright
In the forests of the night,
What immortal hand or eye
Could frame thy fearful symmetry?
In what distant deeps or skies 5
Burnt the fire of thine eyes?
On what wings dare he aspire?
What the hand dare seize the fire?
And what shoulder and what art
Could twist the sinews of thy heart? 10
And when thy heart began to beat,
What dread hand and what dread feet?
What the hammer? what the chain?
In what furnace was thy brain?
What the anvil? What dread grasp 15
Dare its deadly terrors clasp?
When the stars threw down their spears,
And water’d heaven with their tears,
Did He smile His work to see?
Did He who made the lamb make thee? 20
Tiger, tiger, burning bright
In the forests of the night,
What immortal hand or eye
Dare frame thy fearful symmetry?
Thanks a bunch Red,
That’s been bugging me for ages 
Slan,
D.
BTW, my sig is from “Prayer for my Daughter”..one of his greatest poems.
I’ve had mine turned off for a long time, but this thread reminded me of it, so I’ll turn it on again. I can’t tell you exactly where it came from, except that I think it’s from one or another of the Unanishads.
Best wishes,
Jerry
My current one I saw on a piece of mail at work, and I thnk it’s time for a change, even though it is very true for me.
Some mornings it just doesn’t pay to gnaw through the leather straps.
Emo Phillips
Previous ones-
There are only two ways to live your life. One is as though nothing is a miracle. The other is as though everything is a miracle." --A. Einstein
I try to keep this one in mind, to me it is profound.
Heard one hundred drummers whose hands were a-blazin’
I’m also a Scottish Tenor drummer and I like the mental picture this gives me.
Now, I think I’ll go looking for a new quote- I just like the way words go together and sometimes they actually stick in my brain.
My signature line is a reference to the Reasonable Person Principle. http://chiffboard.mati.ca/viewtopic.php?t=10316#RPP
Often, in the past, when I wanted a quote, I consulted http://www.twainquotes.com
There is also a wealth of great quotes online, from Will Rogers.
Mine came as the result of a Chiffy Chat evening of silliness. It came to mean being silly in a bizzarre manner - something you don’t have to explain later, mostly because nobody cares
I’d like to get Quizent into Webster’s.
I had one for a while, and removed it because I was bored looking at it all the time. I do not remember what it was. But I have tried to make a new one.
I mostly go with lyrics from whatever song seems appropriate at the time.
Thank you everyone for sharing your secrets. Now, if I don’t get sidetracked, I’ve got some homework and reading to do.
The most important thing about reading is to read between the lines.
Otherwise one may end up lecturing a leech about how to suck blood.
BTW, my signature is not a quote.