For many years I have always struggled with "civilians" asking what I do for a living. My elevator speech goes something like this:
Normal Person: What do you do?
Me: I'm a script supervisor for features and commercials.
Normal Person: Oh! So you write commercials.
Me: No I'm on set during filming. I sit next to the director and make sure the scenes match and the actors say their lines correctly.
Normal Person: Oh, so your like a producer?
Me: No, I'm a script supervisor, I'm like an on-set editor, I make sure that everything matches, continuity, eye line, so that when an editor puts it together it's seamless. You wouldn't know it was shot out of order.
Normal Person: Oh, so you watch for continuity errors?
Me: That's one part of my job.
Normal Person: I'd be great at your job, I always catch continuity errors in movies! Did you ever see [insert random movie]? There was this one part...
At this point I roll my eyes in my head and just smile and nod as Mr./Mrs. Person recounts all continuity errors that he/she have spotted in movies, perhaps thinking I'll give a knowing nod and respond with something like, "I know that exact spot. The script supervisor never worked again. Sad really."
Another alternate version to the last answer is:
Normal Person: Oh, my friend's cousin was an extra in a movie once. He saw [insert famous person] and got to stand right next to them!
At this point the entire conversation shifts as everyone ooh's and ahh's at the thrilling tail of this now third hand celebrity encounter. If I'm feeling snippy (really, it happens) I may comment that I talk with the actors all the time and run lines with them. Somehow that doesn't seem to hold a candle to the time said friend's cousin told Shelley Long which was the fat free ranch dressing in the catering line.
Not only do I have trouble with strangers, but I also have a friend who never quite understands what I do either. She will go on and on about her niece who works in a post-production house (this is in no way intended to belittle post). One time she told me about how this niece was invited to set once and had to stay 15 feet away from the actors, but managed to get some good pictures. "Isn't that amazing!" she tells me. I nod and respond, "you do realize that I actually not only stand next to... but talk to the actors right?" Somehow that doesn't compute...
What have you said that has worked when you explain what you do? How have you explained what you do in a :30 second elevator speech...clearly I need assistance!