I spent a lot of time with my Dad when I was back home in New Zealand this year. He's a farmer (at heart) and I'm a computer scientist (at heart), and, honestly, we've never had anything in common work-wise, but we get along just fine.
At one stage, while sitting in his boat fishing, he asked me, "What is it you do in your job?"
I said, "Ahhh", because it's hard to enough to explain my job (or Agile) to people who work with computers, let alone a gnarly old farmer who's been semi-retired for the last 10 years and used a computer for the first time when he bought an instruction manual for rebuilding his bulldozer.
My only option, really, was an analogy, but since my dad is a very concrete person it had to be a very concrete analogy. I thought a moment ...
I said, 'You remember how, when I was little, you built your garage and we then lived in it while you helped the carpenter built our house?'
"You remember how we then moved into the house and, when I was about 10, you built on the conservatory?"
"You remember how, some time after I left home, you replaced the conservatory and extended the front room out and bought that huge telly?'
"And, you remember how, a few years ago, you extended my old room and put in your air-con and ensuite? And how Mum now wants to replace the kitchen?"
'Well, I help businesses improve themselves just like you built up your house. They can't afford to build the whole thing perfectly up front, they don't usually know what perfect even looks like, and they want to start using their improvements this year, rather than waiting 5 years, or 20."
"And that's what you do?"
"But do you do that with computers, rather than hammers and nails?"
Five minutes later and Dad said, "And when you do this, do you talk your 2nd son - the practical one - into becoming a builder so it's cheaper to keep extending your house?"
I hope this helps.