Photo by digitaura.
This is fun when you are interviewing job candidates, preferably for something in the coporate universe:
Greet the candidate warmly and guide him or her to a small office. The office door should have a small peephole suitable for observation--the more obvious the better. Invite the candidate to have a seat while you make some preparations. Close the door of the room, leaving the candidate to sit by himself/herself.
Slide a ceiling tile to the side and lower a banana on a string--just out of reach. Then go to the peephole and watch the candidate's reaction.