Whisper to make someone else whisper
This is a nice and funny way to getting someone to whisper to you. Leaning in and talking to someone will instantly cause them to automatically repeat your action and whisper back, regardless of the context or subject.
If you whisper anything really random to them, like “do you prefer French or Italian food?” they will whisper back to you in return, which makes this even more entertaining. Just avoid doing this in front of your supervisor or in an unsuitable environment.