Kind of a rough theme to work with, though it lends itself well to both setting and mechanics, I like it because it makes me think.

I’ve already come up with four ideas and tossed out three of them as being somewhat boring, or uninspired, but I’ve settled on one that allows me to do a small bit of a story at the same time as gameplay.  It should be fun to play, even if it doesn’t end up being the most original thing ever.