Jan Brett signed National Bookfest Poster; obtained in Person September 27, 2008 on the National Mall, Washington DC.  She would only sign one item and I had a poster collection going, so poster it was.  She is a renowned Children's illustrator.  Above is the poster (generic shot; mine is too big to scan in) and below is the actual sig as she did it.  Alas, when I approached the table to get the sig, my hubby wasn't back with the camera battery he'd left in the car (in the charger in our suitcase), so I don't have a photo of her signing it