"Find people around you app - Nobody wants to find people around them and meet them. Trust me."

I've been runing a site the last five years for tabletop gamers to do exactly this. It's busier than ever, I'm spending my nights and weekends hacking on it to keep up, and I expect some of the features I'm working on now to make that growth curve noticeably steeper.

There's huge chicken-and-egg problems in this sort of project, but that difficulty is also why they're valuable.