This one is from Nancy Reagan's (or was is Babs Bush's?) Just Say No to Drugs campaign:
Scene: Two boys, one significantly larger than the other, are talking in an empty school setting. The Big Boy offers the Little Boy something (I think it was pot-but I forget what exactly) and the Little Boy refuses it.
Big Boy: What are you a Chicken?!
Little Boy: No! But you're a turkey! as he runs away
I know that the reason that I've never offered little boys drugs is because I'm afraid of being called a type of farm fowl...Very successful ad...I'm sure it worked for everyone who saw it...