...read this excellently-researched strip by The Oatmeal first. Even when it starts getting a little too depressing for you, finding out who Christopher Columbus *really* was and what he did, keep reading to the end. Because then you'll want to change the name of the Federal holiday to Bartolomé Day, too.
http://theoatmeal.com/comics/columbus_day <http://theoatmeal.com/comics/columbus_day>