We did this in college once. Not the ones where everybody takes a turn addressing the class, but the ones where you have to get up and introduce yourself to people. So I turned around and face the nearest stranger. "Hello, my name is Timmy_TED". And nothing hes hiding his mouth with his hand. He had a very worried look on his face. So I repeated myself. "Hi, my name is Timmy_TED. What's your name?"