Who is Casimir Pulaski, you say? Good question.
He's a Polish guy who fought in the Revolutionary War as a cavalry man. He's known as "the father of American cavalry," I think mostly because he saved George Washington's life. In 2009, he was granted honorary American citizenship, which I guess is cool except he'd already been dead 230 years.
There isn't much else to say about the man, besides he loves freedom. And yet all Chicago Public Schools are closed today, as are Chicago Public Libraries and a plethora of other city and county offices. In honor of Casimir Pulaski Day. The Polish population here has pretty big pull.