To my mind, both elements - rules and setting - must be welcoming to the target group. Obviously, the game also has to be in my library. The first thought that came to mind was Toon, and mentioning it in conversation did get some traction. The game uses old school stats, but is incredibly free-form (avoiding a lot of the negative play experience that comes with "you can't do that"), works well in short one-shots, and everyone's seen and enjoyed the source material.
Breaking It Down
Regardless, what are the main ingredients of an RPG that should be covered in any kind of introduction? I'm wary of initiating a character generation session with the uninitiated, because in the past, I've seen players get discouraged by the difference between their idea on paper and how it actually worked out mechanically in a game. So start with a one-shot with pre-generated characters, and only then move on to building one's own character, and finally, introduce them to a mini-campaign lasting a number of sessions, in a setting that speaks to the entire group? Yes, that sounds reasonable, though I may, as usual, be over-thinking it and extending it too far into the future.
Or I could give them LITERALLY what they asked for, with a quick lesson of the basic concepts, perhaps workshopping some elements (rolling up a character, running a little combat) in the process. This might allow to skip directly to "campaigning" with the fewest number of steps, and be a good platform for a discussion on what elements the group feels is important (interaction or combat? for example), and what setting/premise they might like to explore together.
I don't know. So many options even before we get into those last choices... I'd be glad for any advice from the peanut gallery.