Thank you all for your guesses! The number between 0 and 50,000 that we had written on a piece of paper was:
And so, the winner is: suzi April 16, 2014 at 3:00 PM who guessed: 41,814. Unlike on The Price is Right, it was ok to go over ;-)
Congratulations, Suzi! We'll be in touch to get your mailing address so we can send your prize off to you.