I try not to get too much into it- I have an Atlas tattoo on my forearm, and people always ask me about it. I tell them to look it up...'Google it.' If they seem genuinely interested I might discuss it a little further and then I mention the movies. I try not to push it though- asking people to use their brains tends to scare them away.

What if many of the people that knew how, yet choose to STOP working harder and smarter?
Why would they do this? Watch the movie.

I would say stuff blows up, there is an airplane crash, and people disappear. I would not explain Galt.

Do you remember the part of the movie version of AS1 where John Galt talks to Midas Mulligan outside the café in the rain (right at the beginning)? That would be a good place to start.

I usually say something like [I've given you both sides of the conversation here]

You know that there are always people who are very productive, and those who just ride along and never produce anything but always seem to have enough to eat?
--yeah, uh-hunh
And we keep hearing about how our government wants to do this, or that - remodeling the white house or redesigning the school lunch program - where does the money to do that come from?
--taxes, of course.
Well, what would happen if those productive intelligent people - the ones that pay the taxes - just said "Enough. I quit." and stopped?
--stopped what?
stopped coming to work. like, stopped making sure a power plant keeps running. hot outside today, isn't it? stopped doing whatever productive thing they do.
--what would happen?
You know what would happen because you can _see_ it happening around you.
--*dejected* yeah
Atlas Shrugged tells you what to do about it.
--wow

It can seem long, but the person you're talking to ends up doing most of the thinking for himself.