"Oh I'm a dolphin trainer."
Our rule was that the other one had to back up this claim, using one of a number of aquatic anecdotes and then in turn when an enquiry was made as to their employment, they had to be a bus driver. This would in turn be supported by an amusing tale of transport turmoil. We did it so many times that I once absent mindedly wrote it on my car insurance application.
I mention this only because the other day I was asked if I had any advice for my friend's son who was just starting his first job and it was the only thing I could think of.