To dream the impossible dream

In the musical "Man of La Mancha", the character Cervantes tells the inspiring story of a man that he impersonates, striving to do and be much more than he is, to make the world a better place:

"His name is Alonso Quijana, a country squire no longer young. Being retired, he has much time for books. He studies them from morn till night and often through the night and morn again, and all he reads oppresses him; fills him with indignation at man's murderous ways toward man. He ponders the problem of how to make better a world where evil brings profit and virtue none at all; where fraud and deceit are mingled with truth and sincerity. He broods and broods and broods and broods and finally his brains dry up. He lays down the melancholy burden of sanity and conceives the strangest project ever imagined.... to become a knight-errant, and sally forth into the world in search of adventures; to mount a crusade; to raise up the weak and those in need. No longer will he be plain Alonso Quijana, but a dauntless knight known as Don Quixote de La Mancha.

I am Don Quixote! The Man of La Mancha!
I come in a world of iron to make a world of gold.
The mission of each true knight, his duty — nay — his privilege…
      To dream the impossible dream
      To fight the unbeatable foe
      To bear with unbearable sorrow
      To run where the brave dare not go     
      To right the unrightable wrong
      To love pure and chaste from afar
      To try when your arms are too weary
      To reach the unreachable star
      This is my quest
      To follow that star
      No matter how hopeless
      No matter how far
      To fight for the right
      Without question or pause
      To be willing to march into Hell
      For a heavenly cause
      And I know if I'll only be true
      To this glorious quest
      That my heart will lie peaceful and calm
      When I'm laid to my rest
      And the world will be better for this
      That one man, scorned and covered with scars
      Still strove with his last ounce of courage
      To reach the unreachable star!"

             - from "Man of La Mancha", music by Mitch Leigh and lyrics by Joe Darion

See more dream quotes at:
Quotes on Dreams and Aspiring