Walk up to a stranger in the street and ask him/her what time it is. After they reply, grab them by the shoulders and say, in a slightly frantic tone of voice, “No! What YEAR is it?!” When they reply, look off into the distance, still holding their shoulders, and say, “Then...there’s still time to stop it before...” then suddenly run down the street as fast as you can. Bonus points for wearing strange or tattered clothes.