520. Enter Wal-Mart, with a crazy white wig and a lab coat, by bursting through the front door. Then yell "What year is it?" Once someone, preferably a cashier, tells you the date, run out of the store. Come back five years later in the same manner wearing the same attire, approach the same cashier you did five years prior, ask them the date. Once they give it to you, run about the store like a madman yelling "It worked! It worked!" at the top of your lungs.