Students: "Ah-hahhaha!""Crazy" directly translates to "mentally deranged" or "psychopathic" in Hangul. But it's part of my vocabulary. I often say, "that's crazy," as a synonym for "unusual," "strange" or "silly." I never consciously apply it to be funny, but it's like laughing gas in the classroom.
I suppose a native English speaker calling people and things "psychopathic" could get a laugh.
The boys are especially fascinated by the word. Here's a story written by Bill and Perry:
One day a CRAZY man went to the mad hospital. The doctor was an alien and the nurse was a predator. It was a cloudy, rainy, scary day and the crazy man, who had a crazy girlfriend, wanted medicine. The alien-doctor was kind but the nurse predator was hungry. MMM. The nurse ate the girlfriend! Crazy man was very angry...