Not a joke on the FA, but on a fellow commuting pilot.

During one month, my crew had one of our "nice" check airmen on board every week because he was commuting home. Every week he would grab a seat in the back wearing his uniform because he had a very short connection between the last flight of his trip and this one that got him home.

We figured since he was onboard we would take it upon ourselves to include him in our "welcome aboard" announcement right as we were buttoning up. We would commence with your typical announcement but finish it off with: "and folks today we have the pleasure of having our Public Relations Technical Pilot on board. His job is to provide you, our valued customers, with answers to all of those questions you might have regarding our operations and aircraft. So feel free to engage Captain XXX with whatever questions you might have. He is sitting in seat XX and is always eager to interact with our passengers."

Needless to say, he was bombarded with questions during flight. He didn't much appreciate this little prank (especially after a 13 hour duty day), be we sure did get a laugh out of it.