I like what Benhimself said. I'd go with something like:
"50 some-odd years ago, the world as it was ended. We're what's left. The characters are the people that can scrape something together out of the ruin of the world and try to live instead of just survive. Think Mad Max, for sure, but also [insert your favorite 2 or 3 bits of appropriate media]. The rules are quick to pick up, the characters kick ass, and everything matters. Here's a character splat. Wanna play?"