orionengnr said:I wonder what would have happened if all 12-15 of you just started laughing at him...and didn't quit?
This is an awesome thread. All the responses have been great, but picturing the above situation is the most satisfying.
My suggestion is to respond with "Horsefeathers!" or "Preposterous!" (ideally including more than a little theatrical mock-indignance). This accomplishes two things. It defuses the situation while putting him on the defensive. Meanwhile, you have time to recover so you don't suffer from l'esprit d'escalier.